$ cd examples
$ cat >consumer.c <<EOF
#include <assert.h>
#include <stdio.h>
#include "rdkafka.h"

rd_kafka_resp_err_t callback(void *opaque) {
    printf("callback called with %p\n", opaque);
    return RD_KAFKA_RESP_ERR_NO_ERROR;
}

int main(int argc, char **argv) {
        rd_kafka_conf_res_t err; /* librdkafka API error code */
        char errstr[512];        /* librdkafka API error reporting buffer */

        rd_kafka_conf_t *conf = rd_kafka_conf_new();

        err = rd_kafka_conf_set(conf, "security.protocol", "ssl", errstr, sizeof(errstr));
        assert(err == RD_KAFKA_CONF_OK);

        err = rd_kafka_conf_set(conf, "ssl.ca.location", "/dev/null", errstr, sizeof(errstr));
        assert(err == RD_KAFKA_CONF_OK);

        rd_kafka_resp_err_t rk_err = rd_kafka_conf_interceptor_add_on_conf_destroy(conf, "testing", callback, NULL);
        assert(rk_err == RD_KAFKA_RESP_ERR_NO_ERROR);

        rd_kafka_t *rk = rd_kafka_new(RD_KAFKA_CONSUMER, conf, errstr, sizeof(errstr));
        assert(rk == NULL);
        fprintf(stderr, "%% Failed to create new consumer: %s\n", errstr);

        // Since rk==NULL, the conf is still owned by us, and must be cleaned up to avoid leaks.
        rd_kafka_conf_destroy(conf);

        return 0;
}
EOF
$ make consumer
gcc -g -O2 -fPIC -Wall -Wsign-compare [...] -ldl -lpthread
$ ./consumer
% Failed to create new consumer: ssl.ca.location failed: No further error information available
Segmentation fault: 11

[...]
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
  * frame #0: 0x0000000100094950 consumer`rd_kafka_interceptors_on_conf_destroy + 48
    frame #1: 0x000000010002ac9f consumer`rd_kafka_conf_destroy + 15
    frame #2: 0x00000001000030f9 consumer`main(argc=<unavailable>, argv=<unavailable>) at consumer.c:30:9 [opt]
    frame #3: 0x00000001004b152e dyld`start + 462

(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
  * frame #0: 0x0000000100094920 consumer`rd_kafka_interceptors_on_conf_destroy
    frame #1: 0x000000010002aa3d consumer`rd_kafka_anyconf_destroy + 29
    frame #2: 0x000000010000442b consumer`rd_kafka_destroy_final + 827
    frame #3: 0x00000001000057a6 consumer`rd_kafka_new + 3062
    frame #4: 0x00000001000030cd consumer`main(argc=<unavailable>, argv=<unavailable>) at consumer.c:25:26 [opt]
    frame #5: 0x00000001004b152e dyld`start + 462