On Fri, Jul 12, 2019 at 10:39 AM Allan Streib <astr...@indiana.edu> wrote:
> Probably an elementary question stemming from my lack of C expertise. > > I am trying to complile some C code that includes its own "bcrypt" > function. This is conflicting with the declaration in pwd.h. > > error: conflicting types for 'bcrypt' > int bcrypt(char *, const char *, const char *); > ^ > /usr/include/pwd.h:112:8: note: previous declaration is here > char *bcrypt(const char *, const char *); > > In pwd.h I see that the bcrypt declaration is wrapped in a #if block: > ... > __POSIX_VISIBLE is defined as 200809, so __BSD_VISIBLE should be 0 and > the pwd.h declaration for bcrypt should be skipped? > There are four options here: 1) change the software to not use the name 'bcrypt' for a non-static function. OpenBSD has only been using it for 15 years... 2) If you're going to use the name bcrypt, then don't do so in files that pull in <pwd.h>. (This would be a last choice in my book, as that's a fragile setup) 3) *IF* the software was written to only rely on the interfaces of some version of the POSIX standard, then follow the compilation rules described in that standard. You mention POSIX 2008, so perhaps this software would build when following those rules, passing the compiler -D_POSIX_C_SOURCE=200809L to only declare the symbols from that standard Note that application software should *never* define macros matching the pattern __*_VISIBLE such as __BSD_VISIBLE. Those are in the reserved namespace and on OpenBSD they are set by <sys/cdefs.h> based on the macros specified in the various standards for use by application and build software. The ones you should care about are: _POSIX_C_SOURCE -- standardized: specifies a POSIX version _XOPEN_SOURCE -- standardized: specifies a POSIX + XSI version _ISOC11_SOURCE -- adds C2011 interfaces _BSD_SOURCE -- adds all BSD and obsoleted interfaces Make sense? Philip Guenther
