fd(4)                     FILE FORMATS                      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.

     For convenience in referring  to  standard  input,  standard
     output,  and  standard  error, an additional set of names is
     provided: /dev/fd/0 is a synonym  for  /dev/fd/0,  /dev/fd/1
     for /dev/fd/1, and /dev/fd/2 for /dev/fd/2.

SEE ALSO
     open(2), dup(2)

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




























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