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| Newer page: | version 7 | Last edited on Friday, July 7, 2006 9:44:45 am | by AristotlePagaltzis | |
| Older page: | version 6 | Last edited on Saturday, March 26, 2005 7:24:44 pm | by JohnMcPherson | Revert |
@@ -1,35 +1 @@
-This page describes some programming hints that might help you to write more portable
[C
] code
.
-
-
-!!!File Handling
-
-!File locking
-
-[BSD]-style unixes uses flock(2), which uses "advisory" locks. Ie, a process with sufficient read or write permission can ignore the lock and read/write a file. [SysV]-style unixes use either advisory locks or "mandatory" locks (if enabled in the filesystem), and access them by the fcntl(2) command and a <tt>struct flock</tt> object.
-
-A more portable way (POSIX 1003.1-2001) is to use the lockf(3) function from unistd.h, which will do the correct type of locking for the unix it is compiled on. (In Linux/GNU libc, this function is a wrapper around fcntl(2)).
-
-!!!printf types
-!64bitisms and fixed sized types
-If you have a fixed sized type (eg, uint64_t) and you want to use printf to display it, you need to know the real type of the integer. eg:
-<verbatim>
- uint64_t x;
- printf("%llu",x);
-</verbatim>
-This however will fail on 64bit machines as uint64_t is "long" not "long long".
-
-POSIX defines some macros to use in this case, normally found in inttypes.h. Eg, for an unsigned 64 bit value, use the macro PRIu64. This will
-be substituted for whatever is appropriate on your host - either lu or llu, depending on if you are on a 32bit or 64bit host.eg:
-<verbatim>
- uint64_t x;
- printf("%"PRIu64,x);
-</verbatim>
-
-----
-Other pages:
-
-* HP has a set of C portability notes [online|http://docs.hp.com/en/5074/portability.html], although it targets HP-UX.
-* Intel has a similar set of notes [online|http://www.intel.com/cd/ids/developer/asmo-na/eng/technologies/64bit/200519.htm?page=1] (for porting to [ia64] and [amd64])
-
-----
-Part of CategoryProgramming
+Describe
[CPortabilityNotes
] here
.
