From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.1) Gecko/20021003 Description of problem: Note that isblank is only specified in ISO C99, however, if one uses man pages to code by (and most programmers *do*), then the man page for isblank (which is the ISALPHA man page, and covers the following libc functions: isalnum, isalpha, isascii, isblank, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit, ought to make some reference to this fact, and should equally inform the programmer that they want to #define -std=c99, -std=gnu99 or -D_ISOC99_SOURCE for this particular function (isblank()). The way the man page is presently written, there is no reason to suspect that it is necessary to use an additional #define (or -D command line), as all functions in "man isblank()" are painted with the same brush. In the same way that man pages include "#include" information, this man page should include #define information, where appropriate. (Note the only disclaimer to isblank is under the CONFORMING TO section, which states "isblank() is a GNU extension" Version-Release number of selected component (if applicable): How reproducible: Always Steps to Reproduce: 1. See bug 77246 2. 3. Actual Results: Compile warnings, and possible run time errors if used without the proper type of arguements. Additional info: See https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=77246
Note that isblank is a GNU extension too if not compiling ISO C99 source, in that case you should -D_GNU_SOURCE.
The man pages aren't tied to a particular version. For detailed information about glibc/gcc features, the info pages included with those pages are the authoritative source.