On Tue, Nov 18, 2008 at 3:52 PM, Peter Miller <[EMAIL PROTECTED]> wrote:
> Trying to explain the causes of obscure <errno.h> values is like a > riddle-based mystery tour of Asymmetric Api Land. "Yes, that error > happened; yes, the system knows why; no, the system will not tell you > your crime. Guilty! Ten years imprisonment. Next!" Speaking of which: C programmers learn at primary school that you should only observe errno, not assign to it. If a function returns an error (typically null or -1) then you look at errno to see what's wrong. Almost. For a couple of APIs, including readdir, you *must* assign 0 to errno before calling the function, otherwise you cannot tell whether the function succeeded or failed, as NULL is used for both end-of-file (with errno unchanged, not set to 0) and error (with errno set). If you don't explicitly set it, it will have whatever value it previously contained. I pity the fool who tries to persuade Ulrich to change this (standard-compliant) behaviour. <https://bugs.edge.launchpad.net/bugs/279381> -- Martin <http://launchpad.net/~mbp/> _______________________________________________ coders mailing list coders@slug.org.au http://lists.slug.org.au/listinfo/coders
