Amiga Unix — 68040 · 68060

Manual pages › XENIX system calls (2Z)

rdchk(2Z)

checks to see if there is data to be read

From the original Amiga UNIX 2.1 manual. Some things it mentions may not be in this release.

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 semaphore file or if the file specified doesn't exist.

SEE ALSO

read(2)