DUP2(3C)             INTERACTIVE UNIX System             DUP2(3C)



          NAME
               dup2 - duplicate an open file descriptor

          SYNOPSIS
               int dup2 (fildes, fildes2)
               int fildes, fildes2;

          DESCRIPTION
               The fildes argument 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.

               The dup2 function will fail if one or more of the following
               is 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.


























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