This Cygwin bug:
http://www.cygwin.com/ml/cygwin/2004-05/msg00765.html
appears to be caused by these changes:
2003-08-22 Jeff Johnston <jjohnstn at redhat dot com>
* libc/stdio/vasprintf.c: Ditto. Also call _vfprintf_r directly.
* libc/stdio/vsnprintf.c: Ditto.
* libc/stdio/vsprintf.c: Ditto.
* libc/stdio/snprintf.c: Call _vfprintf_r directly.
* libc/stdio/sprintf.c: Ditto.
* libc/stdio/vprintf.c: Ditto. Also add _REENT_ONLY check.
Calling _vfprintf_r directly avoids the f[lock|unlock]file calls that
would happen if just _vfprintf were called.
I don't understand the reasoning for this change. Could someone please
explain? Thanks.