.\".\" Copyright (C) 1997 Jerry Epplin.  All rights reserved..\".\" Permission is granted to make and distribute verbatim copies of this.\" manual provided the copyright notice and this permission notice are.\" preserved on all copies..\".\" Permission is granted to copy and distribute modified versions of this.\" manual under the conditions for verbatim copying, provided that the.\" entire resulting derived work is distributed under the terms of a.\" permission notice identical to this one.\" .\" The author assumes no responsibility for errors or omissions, or for.\" damages resulting from the use of the information contained herein..\" .\" Formatted or processed versions of this manual, if unaccompanied by.\" the source, must acknowledge the copyright and authors of this work..\".TH RT_SEM_TRYWAIT 2 "21 July 1997" "rt_ipc" "rt_ipc".SH NAMErt_sem_trywait \- semaphore 'wait' operation (without blocking).SH SYNOPSIS.nf.B #define MODULE.B #include <linux/module.h> .B #include <linux/kernel.h> .B #include <linux/version.h> .B #include <linux/errno.h> .B #include "rt_ipc.h".fi.sp.BI "int rt_sem_trywait(rt_sem_t *" sem ");.SH DESCRIPTION.B rt_sem_waitis the semaphore wait (sometimes known as 'take' or 'P') operation.Unlike .BR rt_sem_wait ,.B rt_sem_trywaitreturns immediately whether or not the semaphore is available..I sempoints to the structure used in the call to.BR rt_sem_create ..SH "RETURN VALUE"On success, 0 is returned.  On failure, a negative value is returnedas described below..SH ERRORS.IP \fB-EAGAIN\fPthe semaphore is not currently available..IP \fB-EINVAL\fP.I semdoes not point to a valid rt_sem_t..SH "AUTHOR"Jerry Epplin <JerryEpplin@worldnet.att.net>.SH "SEE ALSO".BR rt_task_ipc_delete (2), .BR rt_task_ipc_init (2), .BR rt_sem_destroy (2), .BR rt_sem_init (2), .BR rt_sem_post (2),.BR rt_sem_wait (2)