* [PATCH v2] msgop.2: add an example program
@ 2015-03-05 1:31 wfp5p-rupya+Y+cgAvmQRmTv5wTA
[not found] ` <1425519063-23013-1-git-send-email-wfp5p-rupya+Y+cgAvmQRmTv5wTA@public.gmane.org>
0 siblings, 1 reply; 2+ messages in thread
From: wfp5p-rupya+Y+cgAvmQRmTv5wTA @ 2015-03-05 1:31 UTC (permalink / raw)
To: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w; +Cc: linux-man-u79uwXL29TY76Z2rM5mHXA
From: Bill Pemberton <wfp5p-rupya+Y+cgAvmQRmTv5wTA@public.gmane.org>
Signed-off-by: Bill Pemberton <wfp5p-rupya+Y+cgAvmQRmTv5wTA@public.gmane.org>
---
man2/msgop.2 | 140 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 138 insertions(+), 2 deletions(-)
diff --git a/man2/msgop.2 b/man2/msgop.2
index d1bd2125344d..2546d241e960 100644
--- a/man2/msgop.2
+++ b/man2/msgop.2
@@ -36,8 +36,6 @@
.\" Language and formatting clean-ups
.\" Added notes on /proc files
.\"
-.\" FIXME Add example programs to this page.
-.\"
.TH MSGOP 2 2015-02-21 "Linux" "Linux Programmer's Manual"
.SH NAME
msgrcv, msgsnd \- System V message queue operations
@@ -578,6 +576,144 @@ this error was not diagnosed by
This bug is fixed
.\" commit 4f87dac386cc43d5525da7a939d4b4e7edbea22c
in Linux 3.14.
+.SH EXAMPLE
+The program below demonstrates the use of
+.BR msgsnd ()
+and
+.BR msgrcv ().
+
+The example program is first run with the \fB\-s\fP option to send a
+message and then run again with the \fB-r\fP option to receive a
+message.
+
+The following shell session shows a sample run of the program:
+.in +4n
+.nf
+
+.RB "$" " ./a.out \-s"
+sent: a message at Wed Mar 4 16:25:45 2015
+
+.RB "$" " ./a.out \-r"
+message received: a message at Wed Mar 4 16:25:45 2015
+
+.fi
+.in
+.SS Program source
+\&
+.nf
+/* msgop.c */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/msg.h>
+
+struct msgbuf {
+ long mtype;
+ char mtext[80];
+};
+
+static void
+usage(char *prog_name, char *msg)
+{
+ if (msg != NULL)
+ fputs(msg, stderr);
+
+ fprintf(stderr, "Usage: %s [options]\\n", prog_name);
+ fprintf(stderr, "Options are:\\n");
+ fprintf(stderr, "\-s send message using msgsnd()\\n");
+ fprintf(stderr, "\-r read message using msgrcv()\\n");
+ fprintf(stderr, "\-t message type (default is 1)\\n");
+ fprintf(stderr, "\-k message queue key (default is 1234)\\n");
+ exit(EXIT_FAILURE);
+}
+
+static void
+send_msg(int qid, int msgtype)
+{
+ struct msgbuf msg;
+ time_t t;
+
+ msg.mtype = msgtype;
+
+ time(&t);
+ snprintf(msg.mtext, sizeof(msg.mtext), "a message at %s", ctime(&t));
+
+ if (msgsnd(qid, (void *) &msg, sizeof(msg.mtext), IPC_NOWAIT) == \-1) {
+ perror("msgsnd error");
+ exit(EXIT_FAILURE);
+ }
+ printf("sent: %s\\n", msg.mtext);
+}
+
+static void
+get_msg(int qid, int msgtype)
+{
+ struct msgbuf msg;
+
+ if (msgrcv(qid, (void *) &msg, sizeof(msg.mtext), msgtype,
+ MSG_NOERROR | IPC_NOWAIT) == \-1) {
+ if (errno != ENOMSG) {
+ perror("msgrcv");
+ exit(EXIT_FAILURE);
+ }
+ printf("No message available for msgrcv()\\n");
+ } else
+ printf("message received: %s\\n", msg.mtext);
+}
+
+int
+main(int argc, char *argv[])
+{
+ int qid, opt;
+ int mode = 0; /* 1 = send, 2 = receive */
+ int msgtype = 1;
+ int msgkey = 1234;
+
+ while ((opt = getopt(argc, argv, "srt:k:")) != \-1) {
+ switch (opt) {
+ case \(aqs\(aq:
+ mode = 1;
+ break;
+ case \(aqr\(aq:
+ mode = 2;
+ break;
+ case \(aqt\(aq:
+ msgtype = atoi(optarg);
+ if (msgtype <= 0)
+ usage(argv[0], "\-t option must be greater than 0\\n");
+ break;
+ case \(aqk\(aq:
+ msgkey = atoi(optarg);
+ break;
+ default:
+ usage(argv[0], "Unrecognized option\\n");
+ }
+ }
+
+ if (mode == 0)
+ usage(argv[0], "must use either \-s or \-r option\\n");
+
+ qid = msgget(msgkey, IPC_CREAT | 0666);
+
+ if (qid == \-1) {
+ perror("msgget");
+ exit(EXIT_FAILURE);
+ }
+
+ if (mode == 2)
+ get_msg(qid, msgtype);
+ else
+ send_msg(qid, msgtype);
+
+ exit(EXIT_SUCCESS);
+}
+.fi
.SH SEE ALSO
.BR msgctl (2),
.BR msgget (2),
--
2.1.0
--
To unsubscribe from this list: send the line "unsubscribe linux-man" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] msgop.2: add an example program
[not found] ` <1425519063-23013-1-git-send-email-wfp5p-rupya+Y+cgAvmQRmTv5wTA@public.gmane.org>
@ 2015-03-09 7:31 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 2+ messages in thread
From: Michael Kerrisk (man-pages) @ 2015-03-09 7:31 UTC (permalink / raw)
To: wfp5p-rupya+Y+cgAvmQRmTv5wTA
Cc: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w, linux-man-u79uwXL29TY76Z2rM5mHXA
Hi Bill,
On 03/05/2015 02:31 AM, wfp5p-rupya+Y+cgAvmQRmTv5wTA@public.gmane.org wrote:
> From: Bill Pemberton <wfp5p-rupya+Y+cgAvmQRmTv5wTA@public.gmane.org>
Looks good! Applied. Thanks very much for the patch!
Cheers,
Michael
> Signed-off-by: Bill Pemberton <wfp5p-rupya+Y+cgAvmQRmTv5wTA@public.gmane.org>
> ---
> man2/msgop.2 | 140 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 138 insertions(+), 2 deletions(-)
>
> diff --git a/man2/msgop.2 b/man2/msgop.2
> index d1bd2125344d..2546d241e960 100644
> --- a/man2/msgop.2
> +++ b/man2/msgop.2
> @@ -36,8 +36,6 @@
> .\" Language and formatting clean-ups
> .\" Added notes on /proc files
> .\"
> -.\" FIXME Add example programs to this page.
> -.\"
> .TH MSGOP 2 2015-02-21 "Linux" "Linux Programmer's Manual"
> .SH NAME
> msgrcv, msgsnd \- System V message queue operations
> @@ -578,6 +576,144 @@ this error was not diagnosed by
> This bug is fixed
> .\" commit 4f87dac386cc43d5525da7a939d4b4e7edbea22c
> in Linux 3.14.
> +.SH EXAMPLE
> +The program below demonstrates the use of
> +.BR msgsnd ()
> +and
> +.BR msgrcv ().
> +
> +The example program is first run with the \fB\-s\fP option to send a
> +message and then run again with the \fB-r\fP option to receive a
> +message.
> +
> +The following shell session shows a sample run of the program:
> +.in +4n
> +.nf
> +
> +.RB "$" " ./a.out \-s"
> +sent: a message at Wed Mar 4 16:25:45 2015
> +
> +.RB "$" " ./a.out \-r"
> +message received: a message at Wed Mar 4 16:25:45 2015
> +
> +.fi
> +.in
> +.SS Program source
> +\&
> +.nf
> +/* msgop.c */
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <time.h>
> +#include <unistd.h>
> +#include <errno.h>
> +#include <sys/types.h>
> +#include <sys/ipc.h>
> +#include <sys/msg.h>
> +
> +struct msgbuf {
> + long mtype;
> + char mtext[80];
> +};
> +
> +static void
> +usage(char *prog_name, char *msg)
> +{
> + if (msg != NULL)
> + fputs(msg, stderr);
> +
> + fprintf(stderr, "Usage: %s [options]\\n", prog_name);
> + fprintf(stderr, "Options are:\\n");
> + fprintf(stderr, "\-s send message using msgsnd()\\n");
> + fprintf(stderr, "\-r read message using msgrcv()\\n");
> + fprintf(stderr, "\-t message type (default is 1)\\n");
> + fprintf(stderr, "\-k message queue key (default is 1234)\\n");
> + exit(EXIT_FAILURE);
> +}
> +
> +static void
> +send_msg(int qid, int msgtype)
> +{
> + struct msgbuf msg;
> + time_t t;
> +
> + msg.mtype = msgtype;
> +
> + time(&t);
> + snprintf(msg.mtext, sizeof(msg.mtext), "a message at %s", ctime(&t));
> +
> + if (msgsnd(qid, (void *) &msg, sizeof(msg.mtext), IPC_NOWAIT) == \-1) {
> + perror("msgsnd error");
> + exit(EXIT_FAILURE);
> + }
> + printf("sent: %s\\n", msg.mtext);
> +}
> +
> +static void
> +get_msg(int qid, int msgtype)
> +{
> + struct msgbuf msg;
> +
> + if (msgrcv(qid, (void *) &msg, sizeof(msg.mtext), msgtype,
> + MSG_NOERROR | IPC_NOWAIT) == \-1) {
> + if (errno != ENOMSG) {
> + perror("msgrcv");
> + exit(EXIT_FAILURE);
> + }
> + printf("No message available for msgrcv()\\n");
> + } else
> + printf("message received: %s\\n", msg.mtext);
> +}
> +
> +int
> +main(int argc, char *argv[])
> +{
> + int qid, opt;
> + int mode = 0; /* 1 = send, 2 = receive */
> + int msgtype = 1;
> + int msgkey = 1234;
> +
> + while ((opt = getopt(argc, argv, "srt:k:")) != \-1) {
> + switch (opt) {
> + case \(aqs\(aq:
> + mode = 1;
> + break;
> + case \(aqr\(aq:
> + mode = 2;
> + break;
> + case \(aqt\(aq:
> + msgtype = atoi(optarg);
> + if (msgtype <= 0)
> + usage(argv[0], "\-t option must be greater than 0\\n");
> + break;
> + case \(aqk\(aq:
> + msgkey = atoi(optarg);
> + break;
> + default:
> + usage(argv[0], "Unrecognized option\\n");
> + }
> + }
> +
> + if (mode == 0)
> + usage(argv[0], "must use either \-s or \-r option\\n");
> +
> + qid = msgget(msgkey, IPC_CREAT | 0666);
> +
> + if (qid == \-1) {
> + perror("msgget");
> + exit(EXIT_FAILURE);
> + }
> +
> + if (mode == 2)
> + get_msg(qid, msgtype);
> + else
> + send_msg(qid, msgtype);
> +
> + exit(EXIT_SUCCESS);
> +}
> +.fi
> .SH SEE ALSO
> .BR msgctl (2),
> .BR msgget (2),
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
To unsubscribe from this list: send the line "unsubscribe linux-man" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2015-03-09 7:31 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-03-05 1:31 [PATCH v2] msgop.2: add an example program wfp5p-rupya+Y+cgAvmQRmTv5wTA
[not found] ` <1425519063-23013-1-git-send-email-wfp5p-rupya+Y+cgAvmQRmTv5wTA@public.gmane.org>
2015-03-09 7:31 ` Michael Kerrisk (man-pages)
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.