NAME

nthm_blocked - test whether all open pipes are busy

SYNOPSIS

#include <nthm/nthm.h>

int nthm_blocked ( int *err )

DESCRIPTION

The nthm_blocked function tests whether or not nthm_select would block if it were called. This capability may be useful for polling the availability of readable pipes.

RETURN VALUE

If there are pipes with threads tethered in the current scope that are still running but none ready to be read, then a successful call to nthm_blocked returns a non-zero value because nthm_select would have blocked if it were called. Otherwise, nthm_blocked returns a zero value either because the call was unsuccessful or because nthm_select would have returned immediately without blocking.

ERRORS

The value of *err is set to non-zero if it is zero on entry and nthm_blocked is unsuccessful for any reason, but is otherwise left unchanged. Errors indicate a failure of some internal consistency check due to memory corruption, misuse of the API, or a bug in nthm. Bug reports including error codes are welcome.

EXAMPLE

This example shows an event loop that interleaves reading of previously opened nthm pipes with other unspecified operations.

while (! err)
   if (nthm_blocked (&err))
      {
        // do something other than waiting for pipes
      }
   else if (err) // not successful
      break;
   else if ((p = nthm_select (&err))  // not blocked
      {
        x = nthm_read (p, &err))
        // do something with data x read from pipe p
      }
   else          // all visible pipes have been read
      break;

SEE ALSO

nthm, nthm_open, nthm_send, nthm_select, nthm_read, nthm_truncate, nthm_truncate_all, nthm_truncated, nthm_enter_scope, nthm_exit_scope, nthm_kill, nthm_kill_all, nthm_killed, nthm_untether, nthm_tether, nthm_sync, nthm_strerror, nthm_busy, pthreads (7)

AUTHOR

Dennis Furey (milonga@delayinsensitive.com)

PROJECT PAGE

https://github.com/gueststar/nthm