rdchk(2XNX)         (XENIX System Compatibility)         rdchk(2XNX)


       NAME
             rdchk - (XENIX) check to see if there is data to be read

       SYNOPSIS
             cc [flag . . . ] flag . . . -lx
             int rdchk(int fdes);

       DESCRIPTION
             rdchk checks to see if a process will block if it attempts to
             read the file designated by fdes.  rdchk returns 1 if there is
             data to be read or if it is the end of the file (EOF).  In
             this context, the proper sequence of calls using rdchk is:

                   if(rdchk(fildes) > 0)
                       read(fildes, buffer, nbytes);

          Return Values
             rdchk returns -1 if an error occurs (for example, EBADF), 0 if
             the process will block if it issues a read and 1 if it is okay
             to read.  EBADF is returned if a rdchk is done on a semaphore
             file or if the file specified doesn't exist.

       REFERENCES
             read(2)
























                           Copyright 1994 Novell, Inc.               Page 1