On 2017-01-28 18:16, Пётр Б. wrote: > Excuse me for vague wording, let me explain it. > I am trying to build Qt under Cygwin. For some mysterious reason > Cygwin compiler does not expose popen with std=c++11 which is > required for Qt > BUT > at the same time the MinGW compiler installed from Cygwin repository > does expose popen with same standard flag. > I did not yet find a convenient way of using MinGW compiler (which > is prefixed) so I am stuggling to get popen exposed. > What is the reason for this difference between MinGW and Cygwin?
Different default options selected during build. > 2017-01-29 3:50 GMT+03:00, Пётр Б. <satnatan...@gmail.com>: >> tchar.h: http://pastebin.com/raw/109n342z >> So I only get popen if _POSIX_ is defined (which is not defined in >> any header, I searched Cygwin folder with file manager). >> stdio.h: http://pastebin.com/raw/jrd2dmzP >> So I only get popen if some conditions which I did not hear about >> are fullfilled. So, what sorcery should I use to get popen? $ fgrep popen -C2 /usr/include/stdio.h #if __MISC_VISIBLE || __POSIX_VISIBLE >= 199209 int _EXFUN(pclose, (FILE *)); FILE * _EXFUN(popen, (const char *, const char *)); #endif $ egrep -B1 '#define\s+__(MISC_VISIBLE\s+1|POSIX_VISIBLE\s+199209)' /usr/include/sys/features.h #ifdef _DEFAULT_SOURCE #define __MISC_VISIBLE 1 -- #elif (_POSIX_C_SOURCE - 0) >= 2 || defined(_XOPEN_SOURCE) #define __POSIX_VISIBLE 199209 So you have to #define _DEFAULT_SOURCE 1, _XOPEN_SOURCE 1, or _POSIX_C_SOURCE 2: some of these may be enabled by using -std=gnu++1[14yz] instead of -std=c++...; roughly speaking the latter enables only ISO/IEC 9899:yyyy standard features and disables POSIX-only features, which are enabled by using -std=gnu++... -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
