On Nov 29 13:22, Tony Cook wrote: > Linux stdio.h exposes the declaration of cuserid() both with standard > version macros and with _GNU_SOURCE: > > tony@mars:~/play$ cat testcuserid.c > #define _GNU_SOURCE > #include > > int main() { > puts(cuserid(NULL)); > return 0; > } > tony@mars:~/play$ gcc -otestcuserid -Werror=all testcuserid.c > tony@mars:~/play$ ./testcuserid > tony > tony@mars:~/play$ uname -a > Linux mars 4.9.0-8-amd64 #1 SMP Debian 4.9.110-3+deb9u4 (2018-08-21) x86_64 GNU/Linux > > while on Cygwin _GNU_SOURCE doesn't expose cuserid(): Thanks, I pushed a patch. https://sourceware.org/git/?p=newlib-cygwin.git;a=commitdiff;h=09870c6e958c Of course, that doesn't make cuserid more portable. The rule given in the Linux man page still applies: "Do not use cuserid()." Corinna -- Corinna Vinschen Cygwin Maintainer