NPROB2

C synopsis

#include <net.h>

int nprobe (struct nmsg *header);

Fortran synopsis

subroutine NPROB (nevent, ntype, nlength, nflags, nready, ierror)

integer nevent, ntype, nlength, nflags, nready, ierror

Overview

If a synchronizing message exists, information about its type, length, and flags is returned.

The nprobe() function accepts a pointer to a network message descriptor, defined in <net.h>. See nsend(2). Only the nh_event and nh_type fields of the network message descriptor must be filled before calling nprobe(). The nh_type and nh_length fields are altered after a successful probe as if nrecv(2) had been called.

Since nprobe() can only examine buffered messages, it cannot be used when buffers are bypassed.

C return value

Upon successful completion, 1 is returned if a synchronizing message is waiting to be received, and 0 is returned if no synchronizing message is waiting. If an error occurred, -1 is returned and the global variable, errno is set to indicate the error.

Fortran return value

Upon successful completion, the nready argument is set to 1 if a synchronizing message is waiting to be received, and 0 if no synchronizing message is waiting.