fd(4)                                                                    fd(4)


NAME
     /dev/fd - file descriptor files

DESCRIPTION
     These files, conventionally called /dev/fd/0, /dev/fd/1, /dev/fd/2, and
     so on, refer to files accessible through file descriptors.  If file
     descriptor n is open, these two system calls have the same effect:

          fd = open("/dev/fd/n",mode);
          fd = dup(n);

     On these files creat(2) is equivalent to open, and mode is ignored.  As
     with dup, subsequent reads or writes on fd fail unless the original file
     descriptor allows the operations.

SEE ALSO
     open(2), dup(2)

DIAGNOSTICS
     open(2) returns -1 and EBADF if the associated file descriptor is not
     open.


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