5 POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/popen.html}
9 Portability problems fixed by Gnulib:
12 Some platforms start the child with closed stdin or stdout if the
13 standard descriptors were closed in the parent:
17 Portability problems not fixed by Gnulib:
20 Some platforms mistakenly set the close-on-exec bit, then if it is
21 cleared by the application, the platform then leaks file descriptors
22 from earlier @code{popen} calls into subsequent @code{popen} children: