DUP2(3C)                             SysV                             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.