58 lines
1.3 KiB
Markdown
58 lines
1.3 KiB
Markdown
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# msg_queue
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This is the Cuttlefish message queue wrapper library, as one of the IPC options available. Below are the example usages running in two separate processes.
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```
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#define MAX_MSG_SIZE 200
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#define NUM_MESSAGES 100
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typedef struct msg_buffer {
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long mesg_type;
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char mesg_text[MAX_MSG_SIZE];
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} msg_buffer;
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int example_send()
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{
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// create message queue with the key 'a'
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int queue_id = msg_queue_create('a');
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struct msg_buffer msg;
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for (int i=1; i <= NUM_MESSAGES; i++) {
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// create message types 1-3
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msg.mesg_type = (i % 3) + 1;
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sprintf(msg.mesg_text, "test %d", i);
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int rc = msg_queue_send(queue_id, &msg, strlen(msg.mesg_text)+1, false);
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if (rc == -1) {
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perror("main: msgsnd");
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exit(1);
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}
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}
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printf("generated %d messages, exiting.\n", NUM_MESSAGES);
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return 0;
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}
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```
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```
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#define MAX_MSG_SIZE 200
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typedef struct msg_buffer {
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long mesg_type;
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char mesg_text[MAX_MSG_SIZE];
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} msg_buffer;
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int example_receive()
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{
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// create message queue with the key 'a'
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int queue_id = msg_queue_create('a');
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struct msg_buffer msg;
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while (1) {
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int rc = msg_queue_receive(queue_id, &msg, MAX_MSG_SIZE, 1, false);
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if (rc == -1) {
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perror("main: msgrcv");
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exit(1);
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}
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printf("Reader '%d' read message: '%s'\n", 1, msg.mesg_text);
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}
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return 0;
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}
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```
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