5 POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9699919799/functions/dup.html}
9 Portability problems fixed by Gnulib:
12 This function is declared in a different header file (namely, @code{<io.h>})
16 This function crashes when invoked with invalid arguments on some platforms:
20 Portability problems not fixed by Gnulib: