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DUP2(3C-SysV)       RISC/os Reference Manual        DUP2(3C-SysV)



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 descrip-
                         tor.

     [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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