> Date: Tue, 13 Apr 2021 19:36:26 +0200 > From: Rafael Sadowski <raf...@sizeofvoid.org> > > Based on my cmake pull-request(1) to fix the cmake build on OpenBSD, the > following question has arisen which is worth analysing? > > "It seems OpenBSD has a strange behavior because macro _POSIX_C_SOURCE is a > standard! @sizeofvoid What are the errors raised if _POSIX_C_SOURCE or > _XOPEN_SOURCE are defined?" -- Marc Chevrier > > [1]: https://gitlab.kitware.com/cmake/cmake/-/merge_requests/6000 > > The following code includes the if-defs from cmake with a simple sstream > include. > > $ cat define_test.cxx > #if !defined(_WIN32) && !defined(__sun) > // POSIX APIs are needed > // NOLINTNEXTLINE(bugprone-reserved-identifier) > # define _POSIX_C_SOURCE 200809L > #endif > #if defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__NetBSD__) > // For isascii > // NOLINTNEXTLINE(bugprone-reserved-identifier) > # define _XOPEN_SOURCE 700 > #endif > > #include <sstream> > int main () { return 0; } > > $ clang++ -std=c++17 define_test.cxx # also with c++11/14 > In file included from define_test.cxx:16: > In file included from /usr/include/c++/v1/sstream:173: > In file included from /usr/include/c++/v1/ostream:140: > In file included from /usr/include/c++/v1/locale:207: > /usr/include/c++/v1/__bsd_locale_fallbacks.h:122:17: error: use of undeclared > identifier 'vasprintf'; did you mean 'vsprintf'? > int __res = vasprintf(__s, __format, __va); > ^ > /usr/include/c++/v1/cstdio:124:9: note: 'vsprintf' declared here > using ::vsprintf; > ^ > In file included from define_test.cxx:16: > In file included from /usr/include/c++/v1/sstream:173: > In file included from /usr/include/c++/v1/ostream:140: > In file included from /usr/include/c++/v1/locale:207: > /usr/include/c++/v1/__bsd_locale_fallbacks.h:122:27: error: cannot initialize > a parameter of type 'char *' with an lvalue of type 'char **' > int __res = vasprintf(__s, __format, __va); > ^~~ > /usr/include/stdio.h:269:21: note: passing argument to parameter here > int vsprintf(char *, const char *, __va_list); > ^ > 2 errors generated > > Looks like, if "_XOPEN_SOURCE 700" or "_POSIX_C_SOURCE 200809L" is defined we > run in this compile error. The question is, is that deliberate?
This is a libc++ issue that isn't really OpenBSD-specific. It would happen on Linux as well if you use libc++. To fix this we need to implement <xlocale.h>. That said, OpenBSD provides the POSIX APIs by default. I believe FreeBSD and NetBSD don't. So your proposed fix makes sense.
