dup2(3C)                                                           dup2(3C)

NAME
     dup2 - duplicate an open file descriptor

SYNOPSIS
     #include <unistd.h>

     int dup2(int fildes, int fildes2);

DESCRIPTION
     fildes is a file descriptor referring to an open file, and fildes2 is
     a non-negative integer less than OPENMAX (the maximum number of open
     files). dup2() causes fildes2 to refer to the same file as fildes. If
     fildes2 already referred to an open file, not fildes, it is closed
     first. If fildes2 refers to fildes, or if fildes is not a valid open
     file descriptor, fildes2 will not be closed first.

     dup2() will fail if one or more of the following are true:

     EBADF    fildes is not a valid open file descriptor.

     EBADF    fildes2 is negative or greater than or equal to OPENMAX.

     EINTR    A signal was caught during the dup2() call.

     EMFILE   OPENMAX file descriptors are currently open.

RESULT
     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.

SEE ALSO
     creat(2), close(2), exec(2), fcntl(2), open(2), pipe(2), lockf(3C),
     limits(4).





















Page 1                       Reliant UNIX 5.44                Printed 11/98