POSIX states: The perror() function shall not change the orientation of the standard error stream. However, cygwin perror() function changes the orientation of stderr to byte-oriented mode if stderr is not oriented yet. Simple test case (chkperror.c) attached checks this behavior. Expected result: 0 äöü: Invalid argument 0 äöü 1 äöü: Invalid argument However, cygwin result: 0 äöü: Invalid argument -1 ▒▒▒ -1 äöü: Invalid argument I have made a patch to solve this problem, attached. However, I am not sure that calling _write_r() here is correct manner. I will appreciate if anyone familiar with libc code comment or make suggestions. -- Takashi Yano <takashi.yano@nifty.ne.jp> -------------- next part -------------- A non-text attachment was scrubbed... Name: 0001-Fix-a-bug-of-perror-which-changes-the-orientation-of.patch Type: application/octet-stream Size: 1690 bytes Desc: not available URL: <http://cygwin.com/pipermail/cygwin/attachments/20180627/97daf6c9/attachment.obj> -------------- next part -------------- A non-text attachment was scrubbed... Name: chkperror.c Type: text/x-csrc Size: 334 bytes Desc: not available URL: <http://cygwin.com/pipermail/cygwin/attachments/20180627/97daf6c9/attachment.bin> -------------- next part -------------- -- 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