2 * Public domain dup2() lookalike
3 * by Curtis Jackson @ AT&T Technologies, Burlington, NC
4 * electronic address: burl!rcj
6 * dup2 performs the following functions:
8 * Check to make sure that fd1 is a valid open file descriptor.
9 * Check to see if fd2 is already open; if so, close it.
10 * Duplicate fd1 onto fd2; checking to make sure fd2 is a valid fd.
11 * Return fd2 if all went well; return BADEXIT otherwise.
14 #include "ruby/config.h"
16 #if defined(HAVE_FCNTL)
20 #if !defined(HAVE_FCNTL) || !defined(F_DUPFD)
27 dup2(int fd1, int fd2)
29 #if defined(HAVE_FCNTL) && defined(F_DUPFD)
32 if (fcntl(fd1, F_GETFL) < 0)
34 if (fcntl(fd2, F_GETFL) >= 0)
39 if (fcntl(fd1, F_DUPFD, fd2) < 0)
47 if (fd1 == fd2) return 0;
49 for (i=0; i<256; i++) {
50 fd = fds[i] = dup(fd1);
56 if (fd == fd2) return 0;