Hello Arkadiusz, On 6/18/20 10:42 PM, Arkadiusz Drabczyk wrote: > I believe new users should be discouraged from using atoi() and that > its disadvantages should be explained. > > I added the information that 0 is returned on error - although C > standard and POSIX say that "If the value of the result cannot be > represented, the behavior is undefined." there are some > interpretations that 0 has to be returned > https://stackoverflow.com/questions/38393162/what-can-i-assume-about-the-behaviour-of-atoi-on-error > and this is also what happens in practice with glibc, musl and uClibc. > > Signed-off-by: Arkadiusz Drabczyk <arkadiusz@xxxxxxxxxxxx> Thanks. Patch applied. I also made a few small tweaks. The results have been pushed to master. Thanks, Michael > --- > man3/atoi.3 | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/man3/atoi.3 b/man3/atoi.3 > index c5894d3..3c6527a 100644 > --- a/man3/atoi.3 > +++ b/man3/atoi.3 > @@ -81,7 +81,18 @@ functions behave the same as > except that they convert the initial portion of the > string to their return type of \fIlong\fP or \fIlong long\fP. > .SH RETURN VALUE > -The converted value. > +The converted value or 0 on error. > +.SH BUGS > +.I errno > +is not set on error so there is no way to distinguish between 0 as an > +error and as the converted value. > +No checks for overflow or underflow are done. > +Only input in decimal base can be converted. > +It's recommended to use > +.BR strtol () > +and > +.BR strtoul () > +family of functions in new programs. > .SH ATTRIBUTES > For an explanation of the terms used in this section, see > .BR attributes (7). > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/
