Initial contribution

src/examples/helloworld/subscriber.c

@@ -0,0 +1,75 @@
+#include "ddsc/dds.h"
+#include "HelloWorldData.h"
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+/* An array of one message (aka sample in dds terms) will be used. */
+#define MAX_SAMPLES 1
+
+int main (int argc, char ** argv)
+{
+    dds_entity_t participant;
+    dds_entity_t topic;
+    dds_entity_t reader;
+    HelloWorldData_Msg *msg;
+    void *samples[MAX_SAMPLES];
+    dds_sample_info_t infos[MAX_SAMPLES];
+    dds_return_t ret;
+    dds_qos_t *qos;
+
+    /* Create a Participant. */
+    participant = dds_create_participant (DDS_DOMAIN_DEFAULT, NULL, NULL);
+    DDS_ERR_CHECK (participant, DDS_CHECK_REPORT | DDS_CHECK_EXIT);
+
+    /* Create a Topic. */
+    topic = dds_create_topic (participant, &HelloWorldData_Msg_desc,
+                              "HelloWorldData_Msg", NULL, NULL);
+    DDS_ERR_CHECK (topic, DDS_CHECK_REPORT | DDS_CHECK_EXIT);
+
+    /* Create a reliable Reader. */
+    qos = dds_qos_create ();
+    dds_qset_reliability (qos, DDS_RELIABILITY_RELIABLE, DDS_SECS (10));
+    reader = dds_create_reader (participant, topic, qos, NULL);
+    DDS_ERR_CHECK (reader, DDS_CHECK_REPORT | DDS_CHECK_EXIT);
+    dds_qos_delete(qos);
+
+    printf ("\n=== [Subscriber] Waiting for a sample ...\n");
+
+    /* Initialize sample buffer, by pointing the void pointer within
+     * the buffer array to a valid sample memory location. */
+    samples[0] = HelloWorldData_Msg__alloc ();
+
+    /* Poll until data has been read. */
+    while (true)
+    {
+        /* Do the actual read.
+         * The return value contains the number of read samples. */
+        ret = dds_read (reader, samples, infos, MAX_SAMPLES, MAX_SAMPLES);
+        DDS_ERR_CHECK (ret, DDS_CHECK_REPORT | DDS_CHECK_EXIT);
+
+        /* Check if we read some data and it is valid. */
+        if ((ret > 0) && (infos[0].valid_data))
+        {
+            /* Print Message. */
+            msg = (HelloWorldData_Msg*) samples[0];
+            printf ("=== [Subscriber] Received : ");
+            printf ("Message (%d, %s)\n", msg->userID, msg->message);
+            break;
+        }
+        else
+        {
+            /* Polling sleep. */
+            dds_sleepfor (DDS_MSECS (20));
+        }
+    }
+
+    /* Free the data location. */
+    HelloWorldData_Msg_free (samples[0], DDS_FREE_ALL);
+
+    /* Deleting the participant will delete all its children recursively as well. */
+    ret = dds_delete (participant);
+    DDS_ERR_CHECK (ret, DDS_CHECK_REPORT | DDS_CHECK_EXIT);
+
+    return EXIT_SUCCESS;
+}