blob: 7c6bbfce11dbf80dae7fe4c79d4c52839a0c68ad [file] [log] [blame]
* Public domain dup2() lookalike
* by Curtis Jackson @ AT&T Technologies, Burlington, NC
* electronic address: burl!rcj
* dup2 performs the following functions:
* Check to make sure that fd1 is a valid open file descriptor.
* Check to see if fd2 is already open; if so, close it.
* Duplicate fd1 onto fd2; checking to make sure fd2 is a valid fd.
* Return fd2 if all went well; return BADEXIT otherwise.
#include <fcntl.h>
#include <unistd.h>
#define BADEXIT -1
dup2(int fd1, int fd2)
if (fd1 != fd2) {
if (fcntl(fd1, F_GETFL) < 0)
return BADEXIT;
if (fcntl(fd2, F_GETFL) >= 0)
if (fcntl(fd1, F_DUPFD, fd2) < 0)
return BADEXIT;
return fd2;