isastream(3C)                    UNIX System V                    isastream(3C)


NAME
      isastream - test a file descriptor

SYNOPSIS
      int isastream(int fildes);

DESCRIPTION
      The function isastream() determines if a file descriptor represents a
      STREAMS file.  fildes refers to an open file.

RETURN VALUE
      If successful, isastream() returns 1 if fildes represents a STREAMS file,
      and 0 if not.  On failure, isastream() returns -1 with errno set to
      indicate an error.

ERRORS
      Under the following conditions, isastream() fails and sets errno to:

      EBADF        fildes is not a valid open file.

SEE ALSO
      streamio(7)
      in the Programmer's Guide: STREAMS































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