Create an Application that Updates Statistic Values

Create the file data_update.c with the following content to update the statistic values in this example. Differences between this sstore_data_update() program and the sstore_data_attach() program described in Create an Application that Writes Statistic Values include the following:

• This sstore_data_update() program has no mystats structure. The mystats structure is used for the memory map in the sstore_data_attach() program.

• The handle to the statistics store is declared but no memory is allocated.

/*
 * Example program data_update.c:
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <libsstore.h>

#define NUM_STATS   2

const char *ssids[NUM_STATS] = {
    "//:class.app/example//:stat.one",
    "//:class.app/example//:stat.two"
};

int main()
{
    sstore_handle_t hdl;
    sstore_value_t vals[NUM_STATS] = {0};
    int i, j;

    if ((hdl = sstore_alloc()) == NULL) {
        fprintf(stderr, "Failed to alloc libsstore handle\n");
        return (-1);
    }

    /* Alloc the sstore_value_t's */
    for (i = 0; i < NUM_STATS; i++) {
        if ((vals[i] = sstore_value_alloc()) == NULL) {
            fprintf(stderr, "Failed to alloc sstore_value_t\n");
            goto end;
        }

        vals[i]->sv_type = SSTORE_VALUE_NUMBER;
    }

    /* Update the stats every second */
    for (i = 0;; i++) {
        char *id, *desc;

        for (j = 0; j < NUM_STATS; j++) {
            vals[j]->sv_value.num += j + 1;
        }

        if (sstore_data_update(hdl, ssids, NUM_STATS,
            vals) != ESSTORE_OK) {
                fprintf(stderr, "Failed to update stats. "
                    "Reason: %s\n", sstore_err_description(hdl));
                break;
        }

        /* Check warnings */
        while (sstore_warning_next(hdl, &id,
            &desc) != SS_WARN_OK) {
                fprintf(stderr, "failed to update stat for %s "
                    "because %s\n", id, desc);
        }

        sleep(1);
    }

end:
    for (i = 0; i < NUM_STATS; i++) {
        sstore_value_free(vals[i]);
    }

    sstore_free(hdl);
    return (0);
}

Compile the application:

$ cc -lsstore -o data_update data_update.c