From: Erik Faye-Lund Date: Wed, 25 May 2011 21:52:44 GMT Subject: Re: [PATCH 2/2] Include unistd.h. Message-ID: In-Reply-To: <7vd3j64oq6.fsf@alter.siamese.dyndns.org> On Wed, May 25, 2011 at 8:30 PM, Junio C Hamano wrote: > mduft@gentoo.org writes: > >> At least on Interix, NULL is defined in unistd.h, and not including it >> causes compilation failure. >> >> Signed-off-by: Markus Duft >> --- >>  compat/fnmatch/fnmatch.c |    1 + >>  1 files changed, 1 insertions(+), 0 deletions(-) >> >> diff --git a/compat/fnmatch/fnmatch.c b/compat/fnmatch/fnmatch.c >> index 14feac7..0238cca 100644 >> --- a/compat/fnmatch/fnmatch.c >> +++ b/compat/fnmatch/fnmatch.c >> @@ -25,6 +25,7 @@ >>  # define _GNU_SOURCE 1 >>  #endif >> >> +#include >>  #include >>  #include >>  #include > > The header stddef.h is where NULL is supposed to be defined, and commonly > used headers are supposed to define NULL the same way as stddef.h does. > There is a conditional inclusion of stdlib.h in fnmatch.c and stdlib.h is > one of those files; probably that is how the upstream pulls in NULL when > compiling this. > > But we don't define STDC_HEADERS nor _LIBC (and we shouldn't), so I don't > know how the existing users of compat/fnmatch/ gets the defintion of NULL > from. Output from "gcc -E -dD -DNO_FNMATCH compat/fnmatch/fnmatch.c" does > not seem to show any NULL defined. > > Other platforms (e.g. SunOS, IRIX, HPUX, Windows) use NO_FNMATCH_CASEFOLD > and compile this file.  How are they getting their NULLs? Windows/MinGW: $ gcc -E -dD -DNO_FNMATCH compat/fnmatch/fnmatch.c | grep NULL compat/fnmatch/fnmatch.c:29:21: error: fnmatch.h: No such file or directory #define __MINGW_ATTRIB_NONNULL(arg) __attribute__ ((__nonnull__ (arg))) #undef __need_NULL #define __need_NULL #undef NULL #define NULL ((void *)0) #undef __need_NULL The "#define NULL ((void *)0)"-line comes from stddef.h, which is included from string.h, which in turn is included by fnmatch.c.