On Tue, Nov 25, 2003 at 04:46:24PM +0200, Enache Adrian wrote: > On Mon, Nov 24, 2003 a.d., Jacques A. Vidrine wrote: > > The application is broken. You must only check errno if you get an > > error indication from the library call. > > Sorry, but I don't see your point. I know when to check for errno. > If you took the little illustrating program for a real life example of > the use of errno, that's unfortunate :-) > > The problem is that the emulated/wrapped close from libc_r does not > behave like the real one. libc_r is leaking some of its guts > (the tricks it's doing with O_NONBLOCK, etc) in the interface. > This is technically a bug. The fix was trivial.
Hello Enache, My point was that this is not technically a bug. According to IEEE Std 1003.1-2001 aka the Single Unix Specification Version 3 (``SUSv3'') aka POSIX, an application must not examine and interpret `errno' unless the library gives an error indication. There are some functions--- strtol and family, sysconf, others--- that have unusual, errno-preserving behavior. These are described individually in the appropriate section of the standard. For these and only these, you can set errno to 0 and check it immediately after the function call to see whether an error has occurred. I believe that includes all functions described in ISO/IEC 9899:1999 (``C99''), as well as some described only in SUSv3. `close' is not a part of C99, nor is it attributed the `unusual', errno-preserving behavior in SUSv3. (By the way, this exact topic was discuss at some length by the the Austin Common Standards Revision Group this past summer.) Cheers, -- Jacques Vidrine NTT/Verio SME FreeBSD UNIX Heimdal [EMAIL PROTECTED] [EMAIL PROTECTED] [EMAIL PROTECTED] [EMAIL PROTECTED] _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "[EMAIL PROTECTED]"