Am 13.05.2020 um 12:21 schrieb Pavel Fedin via Cygwin:
Hello everyone!While compiling various software packages for Cygwin i notice that very often i have to add something like #define _GNU_SOURCE to them in order to compile correctly. Meanwhile on Linux they compile with no problems at all. I've narrowed it down to -std=??? option using a simple test case: --- cut test.cpp --- #include <stdio.h> #include <stdlib.h> #include <string.h> int main(void) { char *p = strdup("hello"); printf("%s\n", p); free(p); return 0; } --- cut test.cpp --- $ g++ test.cpp -o test - compiles OK $ g++ test.cpp -o test -std=c++14 - error: 'strdup' was not declared in this scope; did you mean 'strcmp'? By printing out predefined macros (-dM -E) i found out that -std=something option adds " #define __STRICT_ANSI__ 1" to builtin macros, but removes all *_SOURCE definitions, so _DEFAULT_SOURCE is not triggered any more. I've compared the behavior with Linux system. On Linux -std=c++14 also defines __STRICT_ANSI__, but various *_SOURCE macros are not omitted. Isn't this a Cygwin bug? By the way, clang does not suffer from this problem. Kind regards, Pavel Fedin
strdup is an extension of C standard so strictly behaviour of Cgywin is correct, see /usr/include/sys/features.h for details -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
