On Wed, Oct 5, 2011 at 2:04 AM, Jon Grant <jg@xxxxxxxx> wrote: > Michael Kerrisk wrote, On 04/10/11 06:46: >> >> Hi Jon, >> >> On Tue, Oct 4, 2011 at 1:58 AM, Jon Grant<jg@xxxxxxxx> wrote: >>> >>> Hello >>> >>> Looking at this page: >>> http://man7.org/linux/man-pages/online/pages/man3/printf.3.html >>> >>> "If an output error is encountered, a negative value is returned." >>> >>> I am thinking if this could be clarified. If I call printf(NULL), errno >>> is >>> set to EINVAL, and -1 is returned. >>> >>> Perhaps could be expanded to add: >>> >>> "If a parameter error is encountered, errno set to EINVAL, and -1 is >>> returned. If an output error is encountered, errno set EIO and -1 >>> returned. >> >> The apparently vague wording is deliberate. Glibc may generally return >> -1, but POSIX simply says "a negative value", and that's all that is >> guaranteed to an application. > > Ah ok. Good point. > > Is it worth documenting the Glibc behaviour on the man page in addition to > explaining POSIX spec. I don't think so in this case. It would mislead people into writing less portable code. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Author of "The Linux Programming Interface"; http://man7.org/tlpi/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
