rdchk(2)                  SYSTEM CALLS                   rdchk(2)



NAME
     rdchk - checks to see if there is data to be read

SYNOPSIS
     cc [flag ...] file ... -lx
     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);

DIAGNOSTICS
     rdchk returns -1 if an error occurs (e.g., 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  sema-
     phore file or if the file specified doesn't exist.

SEE ALSO
     read(2)































            Last change: XENIX Compatibility Package            1