5 POSIX specification: @url{http://www.opengroup.org/susv3xsh/sleep.html}
9 Portability problems fixed by Gnulib:
12 This function is missing on some platforms:
13 mingw (2005 or newer).
16 Portability problems not fixed by Gnulib:
19 According to POSIX, the @code{sleep} function may interfere with the program's
20 use of the @code{SIGALRM} signal. On Linux, it doesn't; on other platforms,