Differences between version 4 and predecessor to the previous major change of gethostname(2).
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| Newer page: | version 4 | Last edited on Monday, December 30, 2002 4:14:49 am | by PerryLorier | Revert |
| Older page: | version 1 | Last edited on Tuesday, June 4, 2002 12:23:41 am | by perry | Revert |
@@ -1,91 +1,50 @@
-GETHOSTNAME
-!!!GETHOSTNAME
-NAME
-SYNOPSIS
-DESCRIPTION
-RETURN VALUE
-ERRORS
-CONFORMING TO
-BUGS
-NOTES
-SEE ALSO
-----
!!NAME
-
-, sethostname
- get/set
host name
+gethostname - get host name
!!SYNOPSIS
+ __#include <unistd.h>__
+ __int gethostname(char *__''name''__, size_t__ ''len''__);__
-
-__#include __
-
-
-__int gethostname(char *__''name''__, size_t__
-''len''__);
-int sethostname(const char *__''name''__, size_t__
-''len''__);__
!!DESCRIPTION
+These functions are used to access or to change the host name of the current processor. Note, that on the Internet each interface has a at least one address, and names are associated with addresses, so a machine may (and usually does) have multiple names. gethostname(2) will return the one that the machine identifies itself as.
-
-These functions are used to access or to change the host
-name of the current processor.
!!RETURN VALUE
+On success, zero is returned. On error, -1 is returned, and ''errno'' is set appropriately.
-
-On success, zero is returned. On error, -1 is returned, and
-''errno'' is set appropriately.
!!ERRORS
+;[EINVAL]: ''len'' is negative or, on Linux/i386, ''len'' is smaller than the actual size. (In this last case glibc 2.1 uses [NAMETOOLONG].)
+;[EFAULT]: ''name'' is an invalid address.
+;[NAMETOOLONG]: ''len'' is smaller than the length of the hostname
-
-__EINVAL__
-
-
-''len'' is negative or, for __sethostname__,
-''len'' is larger than the maximum allowed size, or, for
-__gethostname__ on Linux/i386, ''len'' is smaller than
-the actual size. (In this last case glibc 2.1 uses
-ENAMETOOLONG.)
-
-
-__EPERM__
-
-
-For __sethostname__, the caller was not the
-superuser.
-
-
-__EFAULT__
-
-
-''name'' is an invalid address.
!!CONFORMING TO
+SVr4, 4.4BSD (this function first appeared in 4.2BSD). POSIX.1 does not define these functions, but ISO/IEC 9945-1:1990 mentions them in B.4.4.1.
-
-SVr4, 4.4BSD (this function first appeared in 4.2BSD).
-POSIX.1 does not define these functions, but ISO/IEC
-9945-1:1990 mentions them in B.4.4.1.
!!BUGS
+According to the SUSv2, gethostname(2) must return ''len'' bytes (a truncated hostname, NUL-terminated or not) when the hostname is longer. Linux/Alpha (which has a system call gethostname(2)) complies with this requirement, but libc and glibc on Linux/i386 only return an error in this case.
-
-According to the SUSv2, __gethostname__ must return
-''len'' bytes (a truncated hostname, NUL-terminated or
-not) when the hostname is longer. Linux/Alpha (which has a
-system call __gethostname__) complies with this
-requirement, but libc and glibc on Linux/i386 only return an
-error in this case.
!!NOTES
+The definition of success varies. SUSv2 defines ''gethostname()'' as `return possibly truncated hostname', and having a small ''len'' does not cause an error return. Of course it must be possible to be certain that one has obtained the full hostname, and to this end
+SUSv2 guarantees that `Host names are limited to 255 bytes'.
+!!EXAMPLE
+ #include <unistd.h>
+ #include <malloc.h>
+ #include <stdio.h>
+ #include <string.h>
-The definition of success varies. SUSv2 defines
-''
gethostname()'' as `return possibly truncated
-hostname', and having a small ''len'' does not cause an
-error
return. Of course it must be possible to be certain
-that one has obtained the full hostname
, and to this end
-SUSv2 guarantees that `Host names are limited to 255
-bytes'.
-!!SEE ALSO
+ int main(int argc,char **argv)
+ {
+ char domain[[256];
+ int ret=
gethostname(domain,sizeof(domain
));
+ if (ret==-1) {
+ perror("gethostname");
+
return 1;
+ }
+ printf("%s\n"
,domain);
+ free(domain);
+ return ;
+ }
-getdomainname(2), setdomainname(2),
-
-----
+!!SEE ALSO
+
getdomainname(2), setdomainname(2), uname(2)
