After the page dictionary comes the page data which is a full-resolution, uncompressed bitmap representing the page in the printer's output colorspace.

Page Accounting

Printer drivers must handle all page accounting. This means they must send "PAGE:" messages to the standard error file for each page (and in many cases, copy) sent to the printer.

Color Management

Printer drivers can implement their color management via the cupsColorProfile attributes in the PPD file or internally in the driver from a device-independent colorspace. In general, color management performed by the RIP filters is more efficient than that performed inside printer drivers.

For example, the pstoraster filter often only has to perform a color conversion once each time the color is used for multiple output pixels, while the raster filter must convert every pixel on the page.

Device and Bitmap Variables

Besides the standard PostScript page device dictionary variables defined in the Adobe PostScript Level 3 reference manual, the CUPS filters support additional variables that are passed in the page device dictionary header for the page and in some cases control the type of raster data that is generated:

Bitmaps with a colorspace of CUPS_CSPACE_KCMYcm and more than 1 bit per color are transmitted to the raster driver in KCMY colorspace; the driver is responsible for producing the correct separation of normal and light cyan and magenta inks.

Dissecting the HP-PCL Driver

The HP-PCL driver provided with CUPS (rastertohp) converts bitmap data from the raster filters into HP-PCL commands for most PCL-compatible printers. The actual format of the raster data is controlled by the PPD file being used - deskjet.ppd or laserjet.ppd.

PPD Files

PPD files play an important part of all raster printer drivers. Options defined in the PPD file contain PostScript commands that control the raster data that is sent to the printer driver.

A typical CUPS printer driver will include ColorModel, InputSlot, PageSize, PageRegion, and Resolution options. Each option is shown using the standard PPD format:

*OpenUI *PageSize/Media Size: PickOne
*OrderDependency: 10 AnySetup *PageSize
*DefaultPageSize: Letter
*PageSize Letter/US Letter: "<<
/PageSize [612 792]
/ImagingBBox null
>> setpagedevice"
*End
*PageSize Legal/US Legal: "<<
/PageSize [612 1008]
/ImagingBBox null
>> setpagedevice"
*End
*PageSize A4/A4: "<<
/PageSize [595 842]
/ImagingBBox null
>> setpagedevice"
*End
*CloseUI: *PageSize

The OpenUI keyword specifies the new option. The first name is the option with an asterisk (*) in front of it. The first name is usually followed by a slash (/) and a human-readable version of the option name.

Every option must have a default value, specified using the DefaultOption keyword.

Each option begins with the option name followed by the computer and human-readable values. The PostScript commands follow these inside double quotes. PostScript commands can be provided on a single line:

*PageSize A4/A4: "<</PageSize[595 842]/ImagingBBox null>> setpagedevice"

or broken down on separate lines using the End keyword to terminate them:

*PageSize A4/A4: "<<
/PageSize [595 842]
/ImagingBBox null
>> setpagedevice"
*End

The choice of the two formats is usually esthetic. However, each line in a PPD file must not exceed 255 characters, so if your PostScript commands are long you may need to break them up on separate lines.

Reading Raster Data

As with any filter, your printer driver should handle raster data from a filename specified on the command-line or from the standard input. The cupsRasterOpen() function opens a raster stream for printing:

int           fd;   /* File descriptor */
cups_raster_t *ras; /* Raster stream for printing */


/*
 * Check for valid arguments...
 */

if (argc < 6 || argc > 7)
{
 /*
  * We don't have the correct number of arguments; write an error message
  * and return.
  */

  fputs("ERROR: rastertopcl job-id user title copies options [file]\n", stderr);
  return (1);
}

/*
 * Open the page stream...
 */

if (argc == 7)
{
  if ((fd = open(argv[6], O_RDONLY)) == -1)
  {
    perror("ERROR: Unable to open raster file - ");
    sleep(1);
    return (1);
  }
}
else
  fd = 0;

ras = cupsRasterOpen(fd, CUPS_RASTER_READ);

Once you have opened the raster stream you just need to read each page and print it:

cups_raster










  
  
   














 
HOME HELP PREFERENCES


GNU/Linux Documention




t header;
int                  y;
unsigned char        data[8192];

while (cupsRasterReadHeader(ras, &header))
{
  ... initialize the printer ...
  for (y = header.cupsHeight; y > 0; y ++)
  {
    cupsRasterReadPixels(ras, data, header.cupsBytesPerLine);
    ... send raster line to printer ...
  }
}

After you have processed all pages, close the raster stream and return:

cupsRasterClose(ras);

return (0);

5 - Writing Backends

This chapter describes how to write a backend for CUPS. Backends communicate directly with printers and allow printer drivers and filters to send data using any type of connection transparently.

Overview

Backends are special filters that communicate with printers directly. They are treated slightly differently than filters, however, and have some unique requirements.

Security Considerations

Backends are run as the root user, so special care must be taken to avoid potential security violations. In particular, remember that a backend will be able to manipulate disk files, devices, and other resources that potentially could damage a system or printer.

Command-Line Arguments

Besides the standard filter arguments, backends are also run with no arguments to get a list of available devices. This discovery process is described later in this chapter.

Copy Generation

Like filters, backends should send multiple copies of the print file only if a filename is supplied on the command-line. Otherwise the backend should assume that the upstream filter has already added the necessary commands or data to produce the multiple copies.

Page Accounting

Backend filters generally do not do page accounting, however they should at a minimum produce a single page message for each copy that is produced when a filename is present on the command-line. This is because the user selected "raw" printing and no other accounting information is possible.

Exclusive Access

Backends that talk to local character or block devices should open the device file in exclusive mode (O_EXCL) to cooperate with other printers defined for the same device.

Retries

All backends must retry connections to the device. This includes backends that talk to local character or block devices, as the user may define more than one printer queue pointing at the same physical device.

To prevent excess CPU utilitization, the backend should go to sleep for an amount of time between retries; the CUPS-supplied backends retry once every 30 seconds.

Dissecting the Serial Port Backend

The serial port backend provides support for serial printers. Since it does everything a good backend needs to do, it provides an excellent example of what to do.

Supporting Device Discovery

As previously noted, backends are special filter programs that talk to printer devices. Another task a backend must perform is to list the available devices it supports. The backend lists the available devices when no additioanl arguments are supplied on the command-line (i.e. just the command name...)

The serial backend lists devices by looking at serial port files in the /dev directory, by consulting a hardware inventory (IRIX), and in some cases by trying to open the ports to see if they actually exist.

Once it finds a serial port it writes a single line for each port to the standard error file. Each line looks like this:

serial serial:/dev/ttyS0?baud=115200 "Unknown" "Serial Port 1"

The first word "serial" is the device class; this identifies the class of device which can be used to categorize it in user interfaces. CUPS currently recognizes the following classes:

• "file" - a disk file.
• "direct" - a parallel or fixed-rate serial data port, currently used for Centronics, IEEE-1284, and USB printer ports.
• "serial" - a variable-rate serial port.
• "network" - a network connection, typically via AppSocket, HTTP, IPP, LPD, or SMB/CIFS protocols.

After the device class is the device URI, in this case "serial:/dev/ttyS0?baud=115200". This is the URI that should be used by the user to select this port. For serial ports, the "baud=115200" specifies the maximum baud rate supported by the port - the actual value will vary based on the speed the user selects for the printer.

The last two strings are the model and description for the port. The "Unknown" string means that the printer model is unknown - some devices are able to provide a make and model such as "HP DeskJet" that allows users and software to choose an appropriate printer driver more easily. Both the model and description must be enclosed inside double quotes.

Opening the Serial Port

As noted previously, all backends should open device files in exclusive mode, and retry as needed until the port is available. The serial port does this using a do-while loop:

do
{
  if ((fd = open(resource, O_WRONLY | O_NOCTTY | O_EXCL)) == -1)
  {
    if (errno == EBUSY)
    {
      fputs("INFO: Serial port busy; will retry in 30 seconds...\n", stderr);
      sleep(30);
    }
    else
    {
      perror("ERROR: Unable to open serial port device file");
      return (1);
    }
  }
}
while (fd < 0);

If the port is busy or in use by another process, the backend will go to sleep for 30 seconds and try again. If another error is detected a message is sent to the user and the backend aborts the print job until the problem can be corrected.

Writing Data to the Port

Network and character devices pose an interesting problem when writing data to the port - they may not be able to write all of the bytes in your buffer before returning. To work around this problem you must loop until all bytes have been written:

while (nbytes > 0)
{
  if ((wbytes = write(fd, bufptr, nbytes)) < 0)
    if (errno == ENOTTY)
      wbytes = write(fd, bufptr, nbytes);

  if (wbytes < 0)
  {
    perror("ERROR: Unable to send print file to printer");
    break;
  }

  nbytes -= wbytes;
  bufptr += wbytes;
}

The check for the ENOTTY error is needed on some platforms to clear an error from a previous ioctl() call.

Finishing Up

Once you have sent the print file, return 0 if the file printed successfully or 1 if it did not. This will allow the scheduler to stop the print job if there is a device error, preserving the print job for later printing once the problem has been corrected.

A - Software License Agreement

Common UNIX Printing System License Agreement

Copyright 1997-2002 by Easy Software Products
44141 AIRPORT VIEW DR STE 204
HOLLYWOOD, MARYLAND 20636-3111 USA

Voice: +1.301.373.9600
Email: cups-info@cups.org
WWW: http://www.cups.org

Introduction

The Common UNIX Printing System^TM, ("CUPS^TM"), is provided under the GNU General Public License ("GPL") and GNU Library General Public License ("LGPL"), Version 2. A copy of these licenses follow this introduction.

The GNU LGPL applies to the CUPS API library, located in the "cups" subdirectory of the CUPS source distribution and in the "/usr/include/cups" directory and "libcups.a", "libcups_s.a", "libcups.sl", or "libcups.so" files in the binary distributions.

The GNU GPL applies to the remainder of the CUPS distribution, including the "pstoraster" filter which is based upon GNU Ghostscript 5.50 and the "pdftops" filter which is based upon Xpdf 0.93a.

For those not familiar with the GNU GPL, the license basically allows you to:

• Use the CUPS software at no charge.
• Distribute verbatim copies of the software in source or binary form.
• Sell verbatim copies of the software for a media fee, or sell support for the software.
• Distribute or sell printer drivers and filters that use CUPS so long as source code is made available under the GPL.

What this license does not allow you to do is make changes or add features to CUPS and then sell a binary distribution without source code. You must provide source for any new drivers, changes, or additions to the software, and all code must be provided under the GPL or LGPL as appropriate.

The GNU LGPL relaxes the "link-to" restriction, allowing you to develop applications that use the CUPS API library under other licenses and/or conditions as appropriate for your application.

Trademarks

Easy Software Products has trademarked the Common UNIX Printing System, CUPS, and CUPS logo. These names and logos may be used freely in any direct port or binary distribution of CUPS. To use them in derivative products, please contract Easy Software Products for written permission. Our intention is to protect the value of these trademarks and ensure that any derivative product meets the same high-quality standards as the original.

Binary Distribution Rights

Easy Software Products also sells rights to the CUPS source code under a binary distribution license for vendors that are unable to release source code for their drivers, additions, and modifications to CUPS under the GNU GPL and LGPL. For information please contact us at the address shown above.

The Common UNIX Printing System provides a "pstoraster" filter that utilizes the GNU GhostScript 5.50 core to convert PostScript files into a stream of raster images. For binary distribution licensing of this software, please contact:

Miles Jones
Director of Marketing
Artifex Software Inc.
454 Las Gallinas Ave., Suite 108
San Rafael, CA 94903 USA
Voice: +1.415.492.9861
Fax: +1.415.492.9862
EMail: info@arsoft.com

The "pdftops" filter is based on the Xpdf 0.93a software. For binary distribution licensing of this software, please contact:

Derek B. Noonburg
Email: derekn@foolabs.com
WWW: http://www.foolabs.com/xpdf/

Support

Easy Software Products sells software support for CUPS as well as a commercial printing product based on CUPS called ESP Print Pro. You can find out more at our web site:

http://www.easysw.com

GNU GENERAL PUBLIC LICENSE

Version 2, June 1991

Copyright 1989, 1991 Free Software Foundation, Inc.
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

Everyone is permitted to copy and distribute verbatim
copies of this license document, but changing it is not allowed.

Preamble

The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free software--to make sure the software is free for all its users. This General Public License applies to most of the Free Software Foundation's software and to any other program whose authors commit to using it. (Some other Free Software Foundation software is covered by the GNU Library General Public License instead.) You can apply it to your programs, too.

When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things.

To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. These restrictions translate to certain responsibilities for you if you distribute copies of the software, or if you modify it.

For example, if you distribute copies of such a program, whether gratis or for a fee, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights.

We protect your rights with two steps: (1) copyright the software, and (2) offer you this license which gives you legal permission to copy, distribute and/or modify the software.

Also, for each author's protection and ours, we want to make certain that everyone understands that there is no warranty for this free software. If the software is modified by someone else and passed on, we want its recipients to know that what they have is not the original, so that any problems introduced by others will not reflect on the original authors' reputations.

Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone's free use or not licensed at all.

The precise terms and conditions for copying, distribution and modification follow.

GNU GENERAL PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

0. This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License. The "Program", below, refers to any such program or work, and a "work based on the Program" means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either verbatim or with modifications and/or translated into another language. (Hereinafter, translation is included without limitation in the term "modification".) Each licensee is addressed as "you".

Activities other than copying, distribution and modification are not covered by this License; they are outside its scope. The act of running the Program is not restricted, and the output from the Program is covered only if its contents constitute a work based on the Program (independent of having been made by running the Program). Whether that is true depends on what the Program does.

1. You may copy and distribute verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and give any other recipients of the Program a copy of this License along with the Program.

You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.

2. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions:
   1. You must cause the modified files to carry prominent notices stating that you changed the files and the date of any change.
   2. You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License.
   3. if the modified program normally reads commands interactively when run, you must cause it, when started running for such interactive use in the most ordinary way, to print or display an announcement including an appropriate copyright notice and a notice that there is no warranty (or else, saying that you provide a warranty) and that users may redistribute the program under these conditions, and telling the user how to view a copy of this License. (Exception: if the Program itself is interactive but does not normally print such an announcement, your work based on the Program is not required to print an announcement.)

These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.

Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program.

In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.

3. You may copy and distribute the Program (or a work based on it, under Section 2) in object code or executable form under the terms of Sections 1 and 2 above provided that you also do one of the following:
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The source code for a work means the preferred form of the work for making modifications to it. For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable. However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable.

If distribution of executable or object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place counts as distribution of the source code, even though third parties are not compelled to copy the source along with the object code.

4. You may not copy, modify, sublicense, or distribute the Program except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense or distribute the Program is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.
5. You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Program or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Program (or any work based on the Program), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the Program or works based on it.
6. Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You may not impose any further restrictions on the recipients' exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties to this License.
7. If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to patent issues), conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Program at all. For example, if a patent license would not permit royalty-free redistribution of the Program by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Program.

If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the section is intended to apply and the section as a whole is intended to apply in other circumstances.

It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distribution system, which is implemented by public license practices. Many people have made generous contributions to the wide range of software distributed through that system in reliance on consistent application of that system; it is up to the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot impose that choice.

This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.

8. If the distribution and/or use of the Program is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Program under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this License incorporates the limitation as if written in the body of this License.
9. The Free Software Foundation may publish revised and/or new versions of the General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.

Each version is given a distinguishing version number. If the Program specifies a version number of this License which applies to it and "any later version", you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation.

10. If you wish to incorporate parts of the Program into other free programs whose distribution conditions are different, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally.

NO WARRANTY

11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

END OF TERMS AND CONDITIONS

GNU LIBRARY GENERAL PUBLIC LICENSE

Version 2, June 1991

Copyright (C) 1991 Free Software Foundation, Inc.
59 Temple Place - Suite 330, Boston, MA  02111-1307, USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.

[This is the first released version of the library GPL.  It is
 numbered 2 because it goes with version 2 of the ordinary GPL.]

Preamble

The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public Licenses are intended to guarantee your freedom to share and change free software--to make sure the software is free for all its users.

This license, the Library General Public License, applies to some specially designated Free Software Foundation software, and to any other libraries whose authors decide to use it. You can use it for your libraries, too.

When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things.

To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. These restrictions translate to certain responsibilities for you if you distribute copies of the library, or if you modify it.

For example, if you distribute copies of the library, whether gratis or for a fee, you must give the recipients all the rights that we gave you. You must make sure that they, too, receive or can get the source code. If you link a program with the library, you must provide complete object files to the recipients so that they can relink them with the library, after making changes to the library and recompiling it. And you must show them these terms so they know their rights.

Our method of protecting your rights has two steps: (1) copyright the library, and (2) offer you this license which gives you legal permission to copy, distribute and/or modify the library.

Also, for each distributor's protection, we want to make certain that everyone understands that there is no warranty for this free library. If the library is modified by someone else and passed on, we want its recipients to know that what they have is not the original version, so that any problems introduced by others will not reflect on the original authors' reputations.

Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that companies distributing free software will individually obtain patent licenses, thus in effect transforming the program into proprietary software. To prevent this, we have made it clear that any patent must be licensed for everyone's free use or not licensed at all.

Most GNU software, including some libraries, is covered by the ordinary GNU General Public License, which was designed for utility programs. This license, the GNU Library General Public License, applies to certain designated libraries. This license is quite different from the ordinary one; be sure to read it in full, and don't assume that anything in it is the same as in the ordinary license.

The reason we have a separate public license for some libraries is that they blur the distinction we usually make between modifying or adding to a program and simply using it. Linking a program with a library, without changing the library, is in some sense simply using the library, and is analogous to running a utility program or application program. However, in a textual and legal sense, the linked executable is a combined work, a derivative of the original library, and the ordinary General Public License treats it as such.

Because of this blurred distinction, using the ordinary General Public License for libraries did not effectively promote software sharing, because most developers did not use the libraries. We concluded that weaker conditions might promote sharing better.

However, unrestricted linking of non-free programs would deprive the users of those programs of all benefit from the free status of the libraries themselves. This Library General Public License is intended to permit developers of non-free programs to use free libraries, while preserving your freedom as a user of such programs to change the free libraries that are incorporated in them. (We have not seen how to achieve this as regards changes in header files, but we have achieved it as regards changes in the actual functions of the Library.) The hope is that this will lead to faster development of free libraries.

The precise terms and conditions for copying, distribution and modification follow. Pay close attention to the difference between a "work based on the library" and a "work that uses the library". The former contains code derived from the library, while the latter only works together with the library.

Note that it is possible for a library to be covered by the ordinary General Public License rather than by this special one.

TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

0. This License Agreement applies to any software library which contains a notice placed by the copyright holder or other authorized party saying it may be distributed under the terms of this Library General Public License (also called "this License"). Each licensee is addressed as "you".

A "library" means a collection of software functions and/or data prepared so as to be conveniently linked with application programs (which use some of those functions and data) to form executables.

The "Library", below, refers to any such software library or work which has been distributed under these terms. A "work based on the Library" means either the Library or any derivative work under copyright law: that is to say, a work containing the Library or a portion of it, either verbatim or with modifications and/or translated straightforwardly into another language. (Hereinafter, translation is included without limitation in the term "modification".)

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B - Constants

This appendix lists all of the constants that are defined by the CUPS API.

CUPS Constants

Version Number

The CUPS_VERSION constant is a floating-point number representing the API version number. The current version number is 1.0100 which represents CUPS version 1.1.0.

Printer Capabilities

The CUPS_PRINTER constants represent capability bits for printers and classes:

• CUPS_PRINTER_LOCAL - Is a local printer or class.
• CUPS_PRINTER_REMOTE - Is a remote printer or class.
• CUPS_PRINTER_CLASS - Is a class.
• CUPS_PRINTER_BW - Printer prints in black and white.
• CUPS_PRINTER_COLOR - Printer prints in color.
• CUPS_PRINTER_DUPLEX - Printer can print double-sided.
• CUPS_PRINTER_STAPLE - Printer can staple output.
• CUPS_PRINTER_COPIES - Printer can produce multiple copies on its own.
• CUPS_PRINTER_COLLATE - Printer can collate copies.
• CUPS_PRINTER_PUNCH - Printer can punch holes in output.
• CUPS_PRINTER_COVER - Printer can put covers on output.
• CUPS_PRINTER_BIND - Printer can bind output.
• CUPS_PRINTER_SORT - Printer can sort output.
• CUPS_PRINTER_SMALL - Printer can print on media up to 9x14 inches.
• CUPS_PRINTER_MEDIUM - Printer can print on media from 9x14 to 18x24 inches.
• CUPS_PRINTER_LARGE - Printer can print on media larger than 18x24 inches.
• CUPS_PRINTER_VARIABLE - Printer can print on variable or custom media sizes.
• CUPS_PRINTER_IMPLICIT - Is an implicit class.
• CUPS_PRINTER_OPTIONS - All of the printer capability and option bits.

Encodings

CUPS defines the following character set encoding constants:

• CUPS_US_ASCII - US ASCII character set.
• CUPS_UTF_8 - UTF-8 encoding of Unicode.
• CUPS_ISO8859_1 - ISO-8859-1 character set.
• CUPS_ISO8859_2 - ISO-8859-2 character set.
• CUPS_ISO8859_3 - ISO-8859-3 character set.
• CUPS_ISO8859_4 - ISO-8859-4 character set.
• CUPS_ISO8859_5 - ISO-8859-5 character set.
• CUPS_ISO8859_6 - ISO-8859-6 character set.
• CUPS_ISO8859_7 - ISO-8859-7 character set.
• CUPS_ISO8859_8 - ISO-8859-8 character set.
• CUPS_ISO8859_9 - ISO-8859-9 character set.
• CUPS_ISO8859_10 - ISO-8859-10 character set.
• CUPS_ISO8859_13 - ISO-8859-13 character set.
• CUPS_ISO8859_14 - ISO-8859-14 character set.
• CUPS_ISO8859_15 - ISO-8859-15 character set.
• CUPS_WINDOWS_874 - Windows code page 874.
• CUPS_WINDOWS_1250 - Windows code page 1250.
• CUPS_WINDOWS_1251 - Windows code page 1251.
• CUPS_WINDOWS_1252 - Windows code page 1252.
• CUPS_WINDOWS_1253 - Windows code page 1253.
• CUPS_WINDOWS_1254 - Windows code page 1254.
• CUPS_WINDOWS_1255 - Windows code page 1255.
• CUPS_WINDOWS_1256 - Windows code page 1256.
• CUPS_WINDOWS_1257 - Windows code page 1257.
• CUPS_WINDOWS_1258 - Windows code page 1258.
• CUPS_KOI8_R - Russian code page koi8-r.
• CUPS_KOI8_U - Ukrainian code page koi8-r.

HTTP Constants

Limits

The following constants define the limits for strings:

• HTTP_MAX_BUFFER - Size of socket buffer.
• HTTP_MAX_HOST - Maximum length of hostname.
• HTTP_MAX_URI - Maximum length of URI.
• HTTP_MAX_VALUE - Maximum length of field values.

Status Codes

The following status codes can be returned by httpUpdate() :

• HTTP_ERROR - A network error occurred
• HTTP_CONTINUE - Continue response from HTTP proxy
• HTTP_OK - OPTIONS/GET/HEAD/POST/TRACE command was successful
• HTTP_CREATED - PUT command was successful
• HTTP_ACCEPTED - DELETE command was successful
• HTTP_NOT_AUTHORITATIVE - Information isn't authoritative
• HTTP_NO_CONTENT - Successful command
• HTTP_RESET_CONTENT - Content was reset/recreated
• HTTP_PARTIAL_CONTENT - Only a partial file was recieved/sent
• HTTP_MULTIPLE_CHOICES - Multiple files match request
• HTTP_MOVED_PERMANENTLY - Document has moved permanently
• HTTP_MOVED_TEMPORARILY - Document has moved temporarily
• HTTP_SEE_OTHER - See this other link...
• HTTP_NOT_MODIFIED - File not modified
• HTTP_USE_PROXY - Must use a proxy to access this URI
• HTTP_BAD_REQUEST - Bad request
• HTTP_UNAUTHORIZED - Unauthorized to access host
• HTTP_PAYMENT_REQUIRED - Payment required
• HTTP_FORBIDDEN - Forbidden to access this URI
• HTTP_NOT_FOUND - URI was not found
• HTTP_METHOD_NOT_ALLOWED - Method is not allowed
• HTTP_NOT_ACCEPTABLE - Not Acceptable
• HTTP_PROXY_AUTHENTICATION - Proxy Authentication is Required
• HTTP_REQUEST_TIMEOUT - Request timed out
• HTTP_CONFLICT - Request is self-conflicting
• HTTP_GONE - Server has gone away
• HTTP_LENGTH_REQUIRED - A content length or encoding is required
• HTTP_PRECONDITION - Precondition failed
• HTTP_REQUEST_TOO_LARGE - Request entity too large
• HTTP_URI_TOO_LONG - URI too long
• HTTP_UNSUPPORTED_MEDIATYPE - The requested media type is unsupported
• HTTP_SERVER_ERROR - Internal server error
• HTTP_NOT_IMPLEMENTED - Feature not implemented
• HTTP_BAD_GATEWAY - Bad gateway
• HTTP_SERVICE_UNAVAILABLE - Service is unavailable
• HTTP_GATEWAY_TIMEOUT - Gateway connection timed out
• HTTP_NOT_SUPPORTED - HTTP version not supported

Fields

The following fields are indices for each of the standard HTTP fields in HTTP 1/1:

• HTTP_FIELD_ACCEPT_LANGUAGE - Accept-Language
• HTTP_FIELD_ACCEPT_RANGES - Accept-Ranges
• HTTP_FIELD_AUTHORIZATION - Authorization
• HTTP_FIELD_CONNECTION - Connection
• HTTP_FIELD_CONTENT_ENCODING - Content-Encoding
• HTTP_FIELD_CONTENT_LANGUAGE - Content-Language
• HTTP_FIELD_CONTENT_LENGTH - Content-Length
• HTTP_FIELD_CONTENT_LOCATION - Content-Location
• HTTP_FIELD_CONTENT_MD5 - Content-MD5
• HTTP_FIELD_CONTENT_RANGE - Content-Range
• HTTP_FIELD_CONTENT_TYPE - Content-Type
• HTTP_FIELD_CONTENT_VERSION - Content-Version
• HTTP_FIELD_DATE - Date
• HTTP_FIELD_HOST - Host
• HTTP_FIELD_IF_MODIFIED_SINCE - If-Modified-Since
• HTTP_FIELD_IF_UNMODIFIED_SINCE - If-Unmodified-Since
• HTTP_FIELD_KEEP_ALIVE - Keep-Alive
• HTTP_FIELD_LAST_MODIFIED - Last-Modified
• HTTP_FIELD_LINK - Link
• HTTP_FIELD_LOCATION - Location
• HTTP_FIELD_RANGE - Range
• HTTP_FIELD_REFERER - Referer
• HTTP_FIELD_RETRY_AFTER - Retry-After
• HTTP_FIELD_TRANSFER_ENCODING - Transfer-Encoding
• HTTP_FIELD_UPGRADE - Upgrade
• HTTP_FIELD_USER_AGENT - User-Agent
• HTTP_FIELD_WWW_AUTHENTICATE - WWW-Authenticate

IPP Constants

Limits

The following constants define array limits for IPP data:

• IPP_MAX_NAME - Maximum length of an attribute name
• IPP_MAX_VALUES - Maximum number of set-of values that can be read in a request.

Tags

• IPP_TAG_ZERO - Wildcard tag value for searches; also used to separate groups of attributes
• IPP_TAG_OPERATION - Tag for values of type operation
• IPP_TAG_JOB - Tag for values of type job
• IPP_TAG_END - Tag for values of type end
• IPP_TAG_PRINTER - Tag for values of type printer
• IPP_TAG_UNSUPPORTED_GROUP - Tag for values of type unsupported_group
• IPP_TAG_UNSUPPORTED_VALUE - Tag for values of type unsupported_value
• IPP_TAG_DEFAULT - Tag for values of type default
• IPP_TAG_UNKNOWN - Tag for values of type unknown
• IPP_TAG_NOVALUE - Tag for values of type novalue
• IPP_TAG_NOTSETTABLE - Tag for values of type notsettable
• IPP_TAG_DELETEATTR - Tag for values of type deleteattr
• IPP_TAG_ANYVALUE - Tag for values of type anyvalue
• IPP_TAG_INTEGER - Tag for values of type integer
• IPP_TAG_BOOLEAN - Tag for values of type boolean
• IPP_TAG_ENUM - Tag for values of type enum
• IPP_TAG_STRING - Tag for values of type string
• IPP_TAG_DATE - Tag for values of type date
• IPP_TAG_RESOLUTION - Tag for values of type resolution
• IPP_TAG_RANGE - Tag for values of type range
• IPP_TAG_COLLECTION - Tag for values of type collection
• IPP_TAG_TEXTLANG - Tag for values of type textlang
• IPP_TAG_NAMELANG - Tag for values of type namelang
• IPP_TAG_TEXT - Tag for values of type text
• IPP_TAG_NAME - Tag for values of type name
• IPP_TAG_KEYWORD - Tag for values of type keyword
• IPP_TAG_URI - Tag for values of type uri
• IPP_TAG_URISCHEME - Tag for values of type urischeme
• IPP_TAG_CHARSET - Tag for values of type charset
• IPP_TAG_LANGUAGE - Tag for values of type language
• IPP_TAG_MIMETYPE - Tag for values of type mimetype

Resolution Units

The IPP_RES_PER_INCH and IPP_RES_PER_CM constants specify dots per inch and dots per centimeter, respectively.

Finishings

The finishing values specify special finishing operations to be performed on the job.

• IPP_FINISH_NONE - Do no finishing
• IPP_FINISH_STAPLE - Staple the job
• IPP_FINISH_PUNCH - Punch the job
• IPP_FINISH_COVER - Cover the job
• IPP_FINISH_BIND - Bind the job

Orientations

The orientation values specify the orientation of the job.

• IPP_PORTRAIT - No rotation
• IPP_LANDSCAPE - 90 degrees counter-clockwise
• IPP_REVERSE_LANDSCAPE - 90 degrees clockwise
• IPP_REVERSE_PORTRAIT - 180 degrees

Qualities

The quality values specify the desired quality of the print.

• IPP_QUALITY_DRAFT - Draft quality
• IPP_QUALITY_NORMAL - Normal quality
• IPP_QUALITY_HIGH - High quality

Job States

The job state values are used to represent the current job state.

• IPP_JOB_PENDING - Job is pending
• IPP_JOB_HELD - Job is held
• IPP_JOB_PROCESSING - Job is processing
• IPP_JOB_STOPPED - Job is stopped
• IPP_JOB_CANCELLED - Job is cancelled
• IPP_JOB_ABORTED - Job is aborted
• IPP_JOB_COMPLETED - Job is completed

Printer States

The printer state values are used to represent the current printer state.

• IPP_PRINTER_IDLE - Printer is idle
• IPP_PRINTER_PROCESSING - Printer is processing
• IPP_PRINTER_STOPPED - Printer is stopped

Operations

The operation values represent the available IPP operations.

• IPP_PRINT_JOB - Print a file
• IPP_PRINT_URI - Print a URI
• IPP_VALIDATE_JOB - Validate job attributes
• IPP_CREATE_JOB - Create a new job
• IPP_SEND_DOCUMENT - Send a document to a job
• IPP_SEND_URI - Send a URI to a job
• IPP_CANCEL_JOB - Cancel a job
• IPP_GET_JOB_ATTRIBUTES - Get job attributes
• IPP_GET_JOBS - Get a list of all jobs
• IPP_GET_PRINTER_ATTRIBUTES - Get printer attributes
• IPP_HOLD_JOB - Hold a pending job
• IPP_RELEASE_JOB - Release a held job
• IPP_RESTART_JOB - Restart a completed job
• IPP_PAUSE_PRINTER - Pause a printer
• IPP_RESUME_PRINTER - Restart a paused printer
• IPP_PURGE_JOBS - Purge jobs from the queue
• IPP_SET_PRINTER_ATTRIBUTES - Set printer attributes
• IPP_SET_JOB_ATTRIBUTES - Set job attributes
• IPP_GET_PRINTER_SUPPORTED_VALUES - Get printer supported values
• CUPS_GET_DEFAULT - Get the default destination
• CUPS_GET_PRINTERS - Get a list of all printers
• CUPS_ADD_PRINTER - Add or modify a printer
• CUPS_DELETE_PRINTER - Delete a printer
• CUPS_GET_CLASSES - Get a list of all classes
• CUPS_ADD_CLASS - Add or modify a class
• CUPS_DELETE_CLASS - Delete a class
• CUPS_ACCEPT_JOBS - Accept jobs on a printer or class
• CUPS_REJECT_JOBS - Reject jobs on a printer or class
• CUPS_SET_DEFAULT - Set the default destination
• CUPS_GET_DEVICES - Get a list of all devices
• CUPS_GET_PPDS - Get a list of all PPDs
• CUPS_MOVE_JOB - Move a job to a new destination

Status Codes

Status codes are returned by all IPP requests.

• IPP_OK - Request completed with no errors
• IPP_OK_SUBST - Request completed but some attribute values were substituted
• IPP_OK_CONFLICT - Request completed but some attributes conflicted
• IPP_BAD_REQUEST - The request was bad
• IPP_FORBIDDEN - You don't have access to the resource
• IPP_NOT_AUTHENTICATED - You are not authenticated for the resource
• IPP_NOT_AUTHORIZED - You not authorized to access the resource
• IPP_NOT_POSSIBLE - The requested operation cannot be completed
• IPP_TIMEOUT - A timeout occurred
• IPP_NOT_FOUND - The resource was not found
• IPP_GONE - The resource has gone away
• IPP_REQUEST_ENTITY - The request was too large
• IPP_REQUEST_VALUE - The request contained a value that was unknown to the server
• IPP_DOCUMENT_FORMAT - The document format is not supported by the server
• IPP_ATTRIBUTES - Required attributes are missing
• IPP_URI_SCHEME - The URI scheme is not supported
• IPP_CHARSET - The charset is not supported
• IPP_CONFLICT - One or more attributes conflict
• IPP_COMPRESSION_NOT_SUPPORTED - The specified compression is not supported
• IPP_COMPRESSION_ERROR - The compressed data contained an error
• IPP_DOCUMENT_FORMAT_ERROR - The document data contained an error in it
• IPP_DOCUMENT_ACCESS_ERROR - The remote document could not be accessed
• IPP_INTERNAL_ERROR - The server encountered an internal error
• IPP_OPERATION_NOT_SUPPORTED - The requested operation is not supported
• IPP_SERVICE_UNAVAILABLE - The requested service is unavailable
• IPP_VERSION_NOT_SUPPORTED - The IPP request version is not supported
• IPP_DEVICE_ERROR - The output device encountered an error
• IPP_TEMPORARY_ERROR - A temporary error occurred
• IPP_NOT_ACCEPTING - The destination is not accepting jobs
• IPP_PRINTER_BUSY - The destination is busy
• IPP_ERROR_JOB_CANCELLED - The requested job has been cancelled
• IPP_MULTIPLE_JOBS_NOT_SUPPORTED - The server does not support multiple jobs

PPD Constants

PPD Format Version

The PPD_VERSION constant defines a floating point number representing the newest format version that is supported by CUPS, currently 4.3.

PPD User-Interface Types

Each printer option has a type associated with it:

• PPD_UI_BOOLEAN - The user can turn this option on or off
• PPD_UI_PICKONE - The user can choose one option value to use.
• PPD_UI_PICKMANY - The user can choose zero or more option values.

PPD Sections

Some options must be output before others, or in different sections of the output document. The ppd_section_t enumeration defines which section the option must be output in:

• PPD_ORDER_ANY - The option can be output in any of the document, page, or prolog sections of the document
• PPD_ORDER_DOCUMENT - The option must be output in the DocumentSetup section of the document
• PPD_ORDER_EXIT - The option must be output before the document
• PPD_ORDER_JCL - The option must be output in the job control section of the document
• PPD_ORDER_PAGE - The option must be output in the PageSetup section of the document
• PPD_ORDER_PROLOG - The option must be output in the Prolog section of the document

PPD Colorspaces

Each printer has a default colorspace:

• PPD_CS_CMYK - The printer uses CMYK colors by default
• PPD_CS_CMY - The printer uses CMY colors by default
• PPD_CS_GRAY - The printer uses grayscale by default
• PPD_CS_RGB - The printer uses RGB colors by default
• PPD_CS_RGBK - The printer uses RGBK colors by default
• PPD_CS_N - The printer uses a DeviceN colorspace by default

Raster Constants

Raster Sync Words

The CUPS_RASTER_SYNC and CUPS_RASTER_REVSYNC constants define the standard sync words at the beginning of each CUPS raster file.

Raster Stream Modes

The CUPS_RASTER_READ and CUPS_RASTER_WRITE constants are used with the cupsRasterOpen() function to specify a stream for reading or writing.

Raster Boolean Constants

The CUPS_FALSE and CUPS_TRUE constants represent boolean values in the page header.

Raster Jog Values

The cups_jog_t enumeration defines constants for the Jog page device dictionary variable:

• CUPS_JOG_NONE - Do no jogging
• CUPS_JOG_FILE - Jog pages after each file
• CUPS_JOG_JOB - Jog pages after each job
• CUPS_JOG_SET - Jog pages after each set of jobs

Raster Orientation Values

The cups_orient_t enumeration defines constants for the Orientation page device dictionary variable:

• CUPS_ORIENT_0 - Portrait orientation
• CUPS_ORIENT_90 - Landscape orientation
• CUPS_ORIENT_180 - Reverse-portrait orientation
• CUPS_ORIENT_270 - Reverse-landscape orientation

Raster CutMedia Values

The cups_cut_t enumeration defines constants for the CutMedia page device dictionary variable:

• CUPS_CUT_NONE - Do no jogging
• CUPS_CUT_FILE - Cut pages after each file
• CUPS_CUT_JOB - Cut pages after each job
• CUPS_CUT_SET - Cut pages after each set of jobs
• CUPS_CUT_PAGE - Cut each page

Raster AdvanceMedia Values

The cups_advance_t enumeration defines constants for the AdvanceMedia page device dictionary variable:

• CUPS_ADVANCE_NONE - Do no jogging
• CUPS_ADVANCE_FILE - Advance media after each file
• CUPS_ADVANCE_JOB - Advance media after each job
• CUPS_ADVANCE_SET - Advance media after each set of jobs
• CUPS_ADVANCE_PAGE - Advance media for each page

Raster LeadingEdge Values

The cups_edge_t enumeration defines constants for the LeadingEdge page device dictionary variable:

• CUPS_EDGE_TOP - The top of the media is the leading edge
• CUPS_EDGE_RIGHT - The right of the media is the leading edge
• CUPS_EDGE_BOTTOM - The bottom of the media is the leading edge
• CUPS_EDGE_LEFT - The left of the media is the leading edge

Raster Color Order Values

The cups_order_t enumeration defines the possible color value orderings:

• CUPS_ORDER_CHUNKED - CMYK CMYK CMYK
• CUPS_ORDER_BANDED - CCC MMM YYY KKK
• CUPS_ORDER_PLANAR - CCC ... MMM ... YYY ... KKK ...

Raster Colorspace Values

The cups_cspace_t enumeration defines the possible colorspaces:

• CUPS_CSPACE_W - White (luminance)
• CUPS_CSPACE_RGB - Red, green, blue
• CUPS_CSPACE_RGBA - Red, green, blue, alpha
• CUPS_CSPACE_K - Black
• CUPS_CSPACE_CMY - Cyan, magenta, yellow
• CUPS_CSPACE_YMC - Yellow, magenta, cyan
• CUPS_CSPACE_CMYK - Cyan, magenta, yellow, black
• CUPS_CSPACE_YMCK - Yellow, magenta, cyan, black
• CUPS_CSPACE_KCMY - Black, cyan, magenta, yellow
• CUPS_CSPACE_KCMYcm - Black, cyan, magenta, yellow, light cyan, light magenta
• CUPS_CSPACE_GMCK - Metallic yellow (gold), metallic magenta, metallic cyan, black
• CUPS_CSPACE_GMCS - Metallic yellow (gold), metallic magenta, metallic cyan, metallic grey (silver)
• CUPS_CSPACE_WHITE - White pigment (black as white pigment)
• CUPS_CSPACE_GOLD - Gold foil (black as gold foil)
• CUPS_CSPACE_SILVER - Silver foil (black as silver foil)

C - Structures

This appendix describes all of the structures that are defined by the CUPS API.

CUPS Structures

CUPS Destinations

The CUPS destination structure (cups_dest_t) contains information on a specific destination or instance:

CUPS Jobs

The CUPS job structure (cups_job_t) contains information on a specific job:

CUPS Messages

The CUPS messages structure (cups_lang_t) contains the character set, locale name, and messages array:

CUPS Options

The CUPS option structure (cups_option_t) contains the option name and string value:

Networking Structures

HTTP State

The HTTP state structure (http_t) contains the current state of a HTTP request or response:

IPP State

The IPP state structure (ipp_t) contains the current state of a IPP request or response:

Raster Structures

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t">Raster Page Header

The raster page header (cups_raster

int
cupsAddOption(const char *name,
              const char *value,
              int num_options,
      cups_option_t **options);

#include <cups.h>

...

/* Declare the options array */
int           num_options;
cups_option_t *options;

/* Initialize the options array */
num_options = 0;
options     = (cups_option_t *)0;

/* Add options using cupsAddOption() */
num_options = cupsAddOption("media", "letter", num_options, &options);
num_options = cupsAddOption("resolution", "300dpi", num_options, &options);

int
cupsCancelJob(const char *dest,
              int job);

#include <cups.h>

cupsCancelJob("LaserJet", 1);

ipp_t *
cupsDoFileRequest(http_t *http,
                  ipp_t *request,
                  const char *resource,
  const char *filename);

#include <cups.h>

http_t      *http;
cups_lang_t *language;
ipp_t       *request;
ipp_t       *response;

...

/* Get the default language */
language = cupsLangDefault();

/* Create a new IPP request */
request  = ippNew();

request->request.op.operation_id = IPP_PRINT_FILE;
request->request.op.request_id   = 1;

/* Add required attributes */
ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_CHARSET,
             "attributes-charset", NULL, cupsLangEncoding(language));

ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_LANGUAGE,
             "attributes-natural-language", NULL,
             language != NULL ? language->language : "C");

ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_URI, "printer-uri",
             NULL, "ipp://hostname/resource");

ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_NAME, "requesting-user-name",
             NULL, cupsUser());

/* Do the request... */
response = cupsDoFileRequest(http, request, "/resource", "filename.txt");

ipp_t *
cupsDoRequest(http_t *http,
              ipp_t *request,
              const char *resource);

#include <cups.h>

http_t      *http;
cups_lang_t *language;
ipp_t       *request;
ipp_t       *response;

...

/* Get the default language */
language = cupsLangDefault();

/* Create a new IPP request */
request  = ippNew();

request->request.op.operation_id = IPP_GET_PRINTER_ATTRIBUTES;
request->request.op.request_id   = 1;

/* Add required attributes */
ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_CHARSET,
             "attributes-charset", NULL, cupsLangEncoding(language));

ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_LANGUAGE,
             "attributes-natural-language", NULL,
             language != NULL ? language->language : "C");

ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_URI, "printer-uri",
             NULL, "ipp://hostname/resource");

/* Do the request... */
response = cupsDoRequest(http, request, "/resource");

void
cupsFreeOptions(int num_options,
                cups_option_t *options);

#include <cups/cups.h>

int           num_options;
cups_option_t *options;

...

cupsFreeOptions(num_options, options);

int
cupsGetClasses(char ***classes);

#include <cups/cups.h>

int  i;
int  num_classes;
char **classes;

...

num_classes = cupsGetClasses(

...

if (num_classes > 0)
{
  for (i = 0; i <num_classes; i ++)
    free(classes[i]);

  free(classes);
}

const char *
cupsGetDefault(void);

#include <cups/cups.h>

printf("The default destination is %s\n", cupsGetDefault());

const char *
cupsGetOption(const char *name,
              int num_options,
              cups_option_t *options);

#include <cups/cups.h>

int           num_options;
cups_option_t *options;
const char    *media;

...

media = cupsGetOption("media", num_options, options);

const char *
cupsGetPassword(const char *prompt);

#include <cups/cups.h>

char *password;

...

password = cupsGetPassword("Please enter a password:");

const char *
cupsGetPPD(const char *printer);

#include <cups/cups.h>

char *ppd;

...

ppd = cupsGetPPD("printer@hostname");

...

unlink(ppd);

int
cupsGetPrinters(char ***printers);

#include <cups/cups.h>

int  i;
int  num_printers;
char **printers;

...

num_printers = cupsGetPrinters(

...

if (num_printers > 0)
{
  for (i = 0; i <num_printers; i ++)
    free(printers[i]);

  free(printers);
}

const char *
cupsLangDefault(void);

#include <cups/language.h>

cups_lang_t *language;
...

language = cupsLangDefault();

...

cupsLangFree(language);

char *
cupsLangEncoding(cups_lang_t *language);

#include <cups/language.h>

cups_lang_t *language;
char        *encoding;
...

language = cupsLangDefault();
encoding = cupsLangEncoding(language);
...

cupsLangFree(language);

void
cupsLangFlush(void);

#include <cups/language.h>

...

cupsLangFlush();

void
cupsLangFree(cups_lang_t *language);

#include <cups/language.h>

cups_lang_t *language;
...

cupsLangFree(language);

cups_lang_t *
cupsLangGet(const char *name);

#include <cups/language.h>

cups_lang_t *language;

...

language = cupsLangGet("fr");

...

cupsLangFree(language);

char *
cupsLangString(cups_lang_t *language,
               int         message);

#include <cups/language.h>

cups_lang_t *language;
char        *s;
...

language = cupsLangGet("fr");

s = cupsLangString(language, CUPS_MSG_YES);

...

cupsLangFree(language);

ipp_status_t
cupsLastError(void);

#include <cups/cups.h>

ipp_status_t status;

...

status = cupsLastError();

int
cupsMarkOptions(ppd_file_t *ppd,
                int num_options,
                cups_option_t *options);

#include <cups/cups.h>

int           num_options;
cups_option_t *options;
ppd_file_t    *ppd;

...

cupsMarkOptions(ppd, num_options, options);

int
cupsParseOptions(const char *arg,
                 int num_options,
                 cups_option_t **options);

#include <cups/cups.h>

int           num_options;
cups_option_t *options;

...

num_options = 0;
options     = (cups_option_t *)0;
num_options = cupsParseOptions(argv[5], num_options, &options);

int
cupsPrintFile(const char    *printer,
              const char    *filename,
              const char    *title,
      int           num_options,
      cups_option_t *options);

#include <cups/cups.h>

int           num_options;
cups_option_t *options;
int           jobid;

...

jobid = cupsPrintFile("printer@hostname", "filename.ps", "Job Title",
                      num_options, options);

int
cupsPrintFiles(const char    *printer,
               int           num_files,
               const char    **files,
               const char    *title,
       int           num_options,
       cups_option_t *options);

#include <cups/cups.h>

int           num_files;
const char    *files[100];
int           num_options;
cups_option_t *options;
int           jobid;

...

jobid = cupsPrintFiles("printer@hostname", num_files, files,
                       "Job Title", num_options, options);

void
cupsRasterClose(cups_raster_t *ras);

#include <cups/raster.h>

cups_raster_t *ras;

...

cupsRasterClose(ras);

cups_raster_t *
cupsRasterOpen(int fd,
               cups_mode_t mode);

#include <cups/raster.h>

cups_raster_t *ras;

...

ras = cupsRasterOpen(0, CUPS_RASTER_READ);

unsigned
cupsRasterReadHeader(cups_raster_t *ras,
                     cupspage header_t *header);

#include <cups/raster.h>

int                  line;
cups_raster_t        *ras;
cups_raster










  
  
   














 
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t header;
unsigned char        pixels[8192];
...

while (cupsRasterReadHeader(ras, &header))
{
  ...

  for (line = 0; line < header.cupsHeight; line ++)
  {
    cupsRasterReadPixels(ras, pixels, header.cupsBytesPerLine);

    ...
  }
}

unsigned
cupsRasterReadPixels(cups_raster_t *ras,
                     unsigned char *pixels,
     unsigned length);

#include <cups/raster.h>

int                  line;
cups_raster_t        *ras;
cups_raster










  
  
   














 
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t header;
unsigned char        pixels[8192];
...

while (cupsRasterReadHeader(ras, &header))
{
  ...

  for (line = 0; line < header.cupsHeight; line ++)
  {
    cupsRasterReadPixels(ras, pixels, header.cupsBytesPerLine);

    ...
  }
}

unsigned
cupsRasterWriteHeader(cups_raster_t *ras,
                      cupspage header_t *header);

#include <cups/raster.h>

int                  line;
cups_raster_t        *ras;
cups_raster










  
  
   














 
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t header;
unsigned char        pixels[8192];
...

cupsRasterWriteHeader(ras, &header);

for (line = 0; line < header.cupsHeight; line ++)
{
  ...

  cupsRasterWritePixels(ras, pixels, header.cupsBytesPerLine);
}

unsigned
cupsRasterWritePixels(cups_raster_t *ras,
                      unsigned char *pixels,
      unsigned length);

#include <cups/raster.h>

int                  line;
cups_raster_t        *ras;
cups_raster










  
  
   














 
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t header;
unsigned char        pixels[8192];
...

cupsRasterWriteHeader(ras, &header);

for (line = 0; line < header.cupsHeight; line ++)
{
  ...

  cupsRasterWritePixels(ras, pixels, header.cupsBytesPerLine);
}

const char *
cupsServer(void);

#include <cups/cups.h>

const char *server;

server = cupsServer();

void
cupsSetPasswordCB(const char *(*cb)(const char *prompt));

#include <cups/cups.h>

const char *
my_password_cb(const char *prompt)
{
  return (getpass(prompt));
}

...

char *password;

...

cupsSetPasswordCB(my_password_cb);
password = cupsGetPassword("Please enter a password:");

void
cupsSetServer(const char *server);

#include <cups/cups.h>

cupsSetServer("foo.bar.com");

void
cupsSetUser(const char *user);

#include <cups/cups.h>

...

cupsSetUser("root");

char *
cupsTempFile(char *filename,
             int length);

#include <cups/cups.h>

char filename[256];

cupsTempFile(filename, sizeof(filename));

const char *
cupsUser(void);

#include <cups/cups.h>

const char *user;

user = cupsUser();

void httpBlocking(http_t *http, int blocking)

#include <cups/http.h>

http_t *http;

http = httpConnect("server", port);
httpBlocking(http, 0);

int httpCheck(http_t *http);

#include <cups/http.h>

http_t *http;

if (httpCheck(http))
{
  ... do something ...
}

void httpClearFields(http_t *http)

#include <cups/http.h>

http_t *http;

httpClearFields(http);

void httpClose(http_t *http);

#include <cups/http.h>

http_t *http;

httpClose(http);

http_t *httpConnect(const char *hostname, int port);

#include <cups/http.h>

http_t *http;

http = httpConnect(cupsServer(), ippPort());

char *httpDecode64(char *out, const char *in);

#include <cups/http.h>

char encoded_string[255];
char original_string[255];

httpDecode64(original_string, encoded_string);

int httpDelete(http_t *http, const char *uri);

#include <cups/http.h>

http_t *http;

httpDelete(http, "/some/uri");

char *httpEncode64(char *out, const char *in);

#include <cups/http.h>

char encoded_string[255];
char original_string[255];

httpEncode64(encoded_string, original_string);

int httpError(http_t *http);

#include <cups/http.h>

http_t *http;

if (httpError(http))
{
  ... show an error message ...
}

void httpFlush(http_t *http);

#include <cups/http.h>

http_t *http;

httpFlush(http);

int httpGet(http_t *http, const char *uri);

#include <cups/http.h>

http_t *http;

httpGet(http, "/some/uri");

char *httpGets(char *line, int length, http_t *http)

#include <cups/http.h>

http_t *http;
char line[1024];

if (httpGets(line, sizeof(line), http))
{
  ... process the line ...
}

const char *httpGetDateString(time_t time)

#include <cups/http.h>

puts(httpGetDateString(time(NULL)));

time_t httpGetDateTime(const char *date)

#include <cups/http.h>

printf("%d\n", httpGetDateTime("Fri, 30 June 2000 12:34:56 GMT"));

const char *httpGetField(http_t *http, http_field_t field);

#include <cups/http.h>

http_t *http;

httpGet(http, "/some/uri");
while (httpUpdate(http) == HTTP_CONTINUE);

puts(httpGetField(http, HTTP_FIELD_CONTENT_TYPE));

int httpHead(http_t *http, const char *uri);

#include <cups/http.h>

http_t *http;

httpHead(http, "/some/uri");

void httpInitialize(void);

#include <cups/http.h>

httpInitialize();

int httpOptions(http_t *http, const char *uri);

#include <cups/http.h>

http_t *http;

httpOptions(http, "/some/uri");

int httpPost(http_t *http, const char *uri);

#include <cups/http.h>

http_t *http;

httpPost(http, "/some/uri");

int httpPrintf(http_t *http, const char *format, ...);

#include <cups/http.h>

http_t *http;

httpPrintf(http, "GET / HTTP/1.1 \r\n");

int httpPut(http_t *http, const char *uri);

#include <cups/http.h>

http_t *http;

httpDelete(http, "/some/uri");

int httpRead(http_t *http, char *buffer, int length);

#include <cups/http.h>

http_t *http;
char buffer[1024];
int  bytes;

httpGet(http, "/");
while (httpUpdate(http) != HTTP_CONTINUE);
while ((bytes = httpRead(http, buffer, sizeof(buffer) - 1)) > 0)
{
  buffer[bytes] = '\0';
  fputs(buffer, stdout);
}

int httpReconnect(http_t *http);

#include <cups/http.h>

http_t *http;

httpReconnect(http);

void httpSeparate(const char *uri, char *method,
                  char *username, char *host, int *port,
                  char *resource);

char uri[HTTP_MAX_URI];
char method[HTTP_MAX_URI];
char username[HTTP_MAX_URI];
char host[HTTP_MAX_URI];
char resource[HTTP_MAX_URI];
int port;

httpSeparate(uri, method, username, host, &port, resource);

void httpSetField(http_t *http, http_field_t field, const char *value);

#include <cups/http.h>

http_t *http;

httpSetField(http, HTTP_FIELD_AUTHORIZATION, "Basic dfdr34453454325"));
httpGet(http, "/some/uri");
while (httpUpdate(http) == HTTP_CONTINUE);

int httpTrace(http_t *http, const char *uri);

#include <cups/http.h>

http_t *http;

httpTrace(http, "/some/uri");

http_status_t httpUpdate(http_t *http);

#include <cups/http.h>

http_t *http;
http_status_t status;

httpGet(http, "/some/uri");
while ((status = httpUpdate(http)) == HTTP_CONTINUE);
printf("Request status is %d\n", status);

int httpWrite(http_t *http, char *buffer, int length);

#include <cups/http.h>

http_t *http;
FILE *fp;
char buffer[1024];
int  bytes;

httpPost(http, "/");

while ((bytes = fread(buffer, 1, sizeof(buffer), fp)) > 0)
  httpWrite(http, buffer, bytes);

while (httpUpdate(http) != HTTP_CONTINUE);

while ((bytes = httpRead(http, buffer, sizeof(buffer) - 1)) > 0)
{
  buffer[bytes] = '\0';
  fputs(buffer, stdout);
}

ipp_attribute_t *ippAddBoolean(ipp_t *ipp, ipp_tag_t group,
                               const char *name, char value);

#include <cups/ipp.h>

ipp_t *ipp;

ippAddBoolean(ipp, IPP_TAG_OPERATION, "my-jobs", 1);

ipp_attribute_t *ippAddBooleans(ipp_t *ipp, ipp_tag_t group,
                                const char *name, int num_values,
                                const char *values);

#include <cups/ipp.h>

ipp_t *ipp;
char values[10];

ippAddBooleans(ipp, IPP_TAG_OPERATION, "some-attribute", 10, values);

ipp_attribute_t *ippAddDate(ipp_t *ipp, ipp_tag_t group,
                            const char *name, ipp_uchar_t *value);

#include <cups/ipp.h>

ipp_t *ipp;

ippAddDate(ipp, IPP_TAG_OPERATION, "some-attribute", 
           ippTimeToDate(time(NULL));

ipp_attribute_t *ippAddInteger(ipp_t *ipp, ipp_tag_t group,
                               ipp_tag_t tag, const char *name,
                               int value);

#include <cups/ipp.h>

ipp_t *ipp;

ippAddInteger(ipp, IPP_TAG_OPERATION, "limit", 100);

ipp_attribute_t *ippAddIntegers(ipp_t *ipp, ipp_tag_t group,
                                ipp_tag_t tag, const char *name,
                                int num_values, const int *values);

#include <cups/ipp.h>

ipp_t *ipp;
int values[100];

ippAddIntegers(ipp, IPP_TAG_OPERATION, "some-attribute", 100, values);

ipp_attribute_t *ippAddRange(ipp_t *ipp, ipp_tag_t group,
                             const char *name, int low,
                             int high);

#include <cups/ipp.h>

ipp_t *ipp;

ippAddRange(ipp, IPP_TAG_OPERATION, "page-ranges", 1, 10);

ipp_attribute_t *ippAddRanges(ipp_t *ipp, ipp_tag_t group,
                              const char *name, int num_values,
                              const int *lows, const int *highs);

#include <cups/ipp.h>

ipp_t *ipp;
int lows[2];
int highs[2];

ippAddRanges(ipp, IPP_TAG_OPERATION, "page-ranges", 2, lows, highs);

ipp_attribute_t *ippAddResolution(ipp_t *ipp, ipp_tag_t group,
                                  const char *name, int xres,
                                  int yres, ipp_res_t units);

#include <cups/ipp.h>

ipp_t *ipp;

ippAddBoolean(ipp, IPP_TAG_OPERATION, "printer-resolution",
              720, 720, IPP_RES_PER_INCH);

ipp_attribute_t *ippAddResolutions(ipp_t *ipp, ipp_tag_t group,
                                   const char *name, int num_values,
                                   const int *xres, const int *yres,
                                   const ipp_res_t *units);

#include <cups/ipp.h>

ipp_t *ipp;
int xres[5];
int yres[5];
ipp_res_t units[5];

ippAddBoolean(ipp, IPP_TAG_OPERATION, "printer-resolutions-supported",
              5, xres, yres, units);

ipp_attribute_t *ippAddSeparator(ipp_t *ipp);

#include <cups/ipp.h>

ipp_t *ipp;

ippAddSeparator(ipp);

ipp_attribute_t *ippAddString(ipp_t *ipp, ipp_tag_t group,
                              ipp_tag_t tag, const char *name,
                              const char *charset, const char *value);

#include <cups/ipp.h>

ipp_t *ipp;

ippAddString(ipp, IPP_TAG_OPERATION, IPP_TAG_NAME, "job-name",
             NULL, "abc123");

ipp_attribute_t *ippAddStrings(ipp_t *ipp, ipp_tag_t group,
                               ipp_tag_t tag, const char *name,
                               int num_values, const char *charset,
                               const char **values);

#include <cups/ipp.h>

ipp_t *ipp;
char *values[2] = { "one", "two" };

ippAddStrings(ipp, IPP_TAG_OPERATION, IPP_TAG_KEYWORD, "attr-name",
              2, NULL, values);

time_t ippDateToTime(const ipp_uchar_t date[11]);

#include <cups/ipp.h>

ipp_uchar_t date[11];

printf("UNIX time is %d\n", ippDateToTime(date));

void ippDelete(ipp_t *ipp);

#include <cups/ipp.h>

ipp_t *ipp;

ippDelete(ipp);

ipp_attribute_t *ippFindAttribute(ipp_t *ipp, const char *name, ipp_tag_t tag);

ipp_attribute_t *attr;

attr = ippFindAttribute(response, "printer-state-message", IPP_TAG_TEXT);

int ippLength(ipp_t *ipp);

printf("The length of the response is %d bytes.\n", ippLength(response));

ipp_t *ippNew(void);

#include <cups/ipp.h>

ipp_t *ipp;

ipp = ippNew();

int ippPort(void);

#include <cups/http.h>
#include <cups/ipp.h>

http_t *http;

http = httpConnect(cupsServer(), ippPort());

ipp_state_t ippRead(http_t *http, ipp_t *ipp);

#include <cups/http.h>
#include <cups/ipp.h>

http_t *http;
ipp_t *ipp;
ipp_state_t status;

ipp = ippNew();

while ((status = ippRead(http, ipp)) != IPP_ERROR)
  if (status == IPP_DATA)
    break;

if (status == IPP_DATA)
{
  ... read additional non-IPP data using httpRead() ...
}

void
ippSetPort(int port);

#include <cups/http.h>
#include <cups/ipp.h>

...

ippSetPort(8631);

ipp_uchar_t *ippTimeToDate(time_t time);

#include <cups/ipp.h>

ipp_uchar_t *date;

date = ippTimeToDate(time(NULL));

ipp_state_t ippWrite(http_t *http, ipp_t *ipp);

#include <cups/http.h>
#include <cups/ipp.h>

http_t *http;
ipp_t *ipp;
ipp_state_t status;

ipp = ippNew();
... add attributes ...

while ((status = ippWrite(http, ipp)) != IPP_ERROR)
  if (status == IPP_DATA)
    break;

if (status == IPP_DATA)
{
  ... read additional non-IPP data using httpWrite() ...
}

void ppdClose(ppd_file_t *ppd);

#include <cups/ppd.h>

ppd_file_t *ppd;

ppdClose(ppd);

int ppdConflicts(ppd_file_t *ppd);

#include <cups/ppd.h>

ppd_file_t *ppd;

printf("%d conflicts\n", ppdConflicts(ppd));

int ppdEmit(ppd_file_t *ppd, FILE *file, ppd_section_t section);

#include <cups/ppd.h>

ppd_file_t *ppd;

ppdEmit(ppd, stdout, PPD_ORDER_PAGE);

int ppdEmitFd(ppd_file_t *ppd, int fd, ppd_section_t section);

#include <cups/ppd.h>

ppd_file_t *ppd;

ppdEmitFd(ppd, 1, PPD_ORDER_PAGE);

ppd_choice_t *ppdFindChoice(ppd_option_t *option, const char *choice);

#include <cups/ppd.h>

ppd_file_t *ppd;
ppd_option_t *option;
ppd_choice_t *choice;

option = ppdFindOption(ppd, "PageSize");
choice = ppdFindChoice(option, "Letter");

ppd_choice_t *ppdFindMarkedChoice(ppd_file_t *ppd, const char *keyword);

#include <cups/ppd.h>

ppd_file_t *ppd;
ppd_choice_t *choice;

choice = ppdFindMarkedChoice(ppd, "PageSize");

ppd_option_t *ppdFindOption(ppd_file_t *ppd, const char *keyword);

#include <cups/ppd.h>

ppd_file_t *ppd;
ppd_option_t *option;

option = ppdFindOption(ppd, "PageSize");

int ppdIsMarked(ppd_file_t *ppd, const char *keyword, char char *choice);

#include <cups/ppd.h>

ppd_file_t *ppd;

printf("Letter size %s selected.\n",
       ppdIsMarked(ppd, "PageSize", "Letter") ? "is" : "is not");

void ppdMarkDefaults(ppd_file_t *ppd);

#include <cups/ppd.h>

ppd_file_t *ppd;

ppdMarkDefaults(ppd);

int ppdMarkOption(ppd_file_t *ppd, const char *keyword, const char *choice);

#include <cups/ppd.h>

ppd_file_t *ppd;

ppdMarkOption(ppd, "PageSize", "Letter");

ppd_file_t *ppdOpen(FILE *file);

#include <cups/ppd.h>

ppd_file_t *ppd;
FILE *file;

file = fopen("filename.ppd", "rb");
ppd = ppdOpen(file);
fclose(file);

ppd_file_t *ppdOpenFd(int fd);

#include <cups/ppd.h>

ppd_file_t *ppd;
int        fd;

fd = open("filename.ppd", O_RDONLY);
ppd = ppdOpenFd(fd);
close(fd);

ppd_file_t *ppdOpenFile(const char *filename);

#include <cups/ppd.h>

ppd_file_t *ppd;

ppd = ppdOpenFile("filename.ppd");

float ppdPageLength(ppd_file_t *ppd, const char *name);