DUP2(3C) DUP2(3C)
NAME
dup2 - duplicate an open file descriptor
SYNOPSIS
int dup2 (fildes, fildes2)
int fildes, fildes2;
DESCRIPTION
Fildes is a file descriptor referring to an open file, and
fildes2 is a non-negative integer less than NOFILES. dup2
causes fildes2 to refer to the same file as fildes. If
fildes2 already referred to an open file, it is closed
first.
dup2 will fail if one or more of the following are true:
[EBADF] Fildes is not a valid open file descriptor.
[EMFILE] NOFILES file descriptors are currently open.
SEE ALSO
creat(2), close(2), exec(2), fcntl(2), open(2), pipe(2),
lockf(3C).
DIAGNOSTICS
Upon successful completion a non-negative integer, namely
the file descriptor, is returned. Otherwise, a value of -1
is returned and errno is set to indicate the error.
Page 1 May 1989