fileno(3S)                                                       fileno(3S)




 NAME
      fileno(), fileno_unlocked() - map stream pointer to file descriptor

 SYNOPSIS
      #include <stdio.h>

      int fileno(FILE *stream);

      int fileno_unlocked(FILE *stream);

 DESCRIPTION
      fileno() returns the integer file descriptor associated with the named
      stream; see open(2).

      The following symbolic values in <unistd.h> define the file
      descriptors associated with stdin, stdout, and stderr when a program
      is started :

           STDIN_FILENO        Value of zero for standard input, stdin.
           STDOUT_FILENO       Value of 1 for standard output, stdout.
           STDERR_FILENO       Value of 2 for standard error, stderr.

      fileno_unlocked is identical to fileno except it does not perform any
      internal locking of the stream for multi-thread applications.
      fileno_unlocked can be used by multi-thread applications which have
      already used flockfile() to acquire a mutual exclusion lock for the
      stream (see flockfile(3S)).

 RETURN VALUE
      Upon error, fileno() and fileno_unlocked() return -1.

 SEE ALSO
      open(2), flockfile(3S), fopen(3S).

 STANDARDS CONFORMANCE
      fileno(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1


















 Hewlett-Packard Company            - 1 -    HP-UX Release 10.20:  July 1996