#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>

#define LIBGPS_PATH "./gpsd/libgps.so"
#define LIBGPSD_PATH "./gpsd/libgpsd.so"

#include "gpsd/gpsd.h"

/*
 * Each application used to be forced to define these two entry points,
 * so most of them just copied gpsd.c's. This is no longer necessary.
 */
#if 0
ssize_t gpsd_write(struct gps_device_t *session,
                   const char *buf,
                   const size_t len)
/* pass low-level data to devices straight through */
{
    return gpsd_serial_write(session, buf, len);
}

void gpsd_report(const int debuglevel, const int errlevel,
                 const char *fmt, ...)
{
    va_list ap;

    va_start(ap, fmt);
    gpsd_labeled_report(debuglevel, errlevel, "gpsd:", fmt, ap);
    va_end(ap);

}

#endif /* end gpsd.c copy'n'pasta */

int main(int argc, char **argv)
{
	void *libgps;
	void *libgpsd;
	int flags =
		// No effect on behaviour
		RTLD_LAZY

		/* Necessary so that libgps's symbols will be available to libgpsd.
		 *
		 * libgpsd depends on libgps's symbols, but is not explicitly
		 * linked against libgps. Therefore the dynamic linker will not
		 * automatically load libgps when loading libgpsd.
		 * So we need to help the dynamic linker, by (in order):
		 * 1. Loading libgps with RTLD_GLOBAL, so that its symbols will be
		 *    available to libraries loaded later on, such as libgpsd, then
		 * 2. Loading libgpsd.
		 */
		| RTLD_GLOBAL
	;

	libgps = dlopen(LIBGPS_PATH, flags);
	if (NULL == libgps) {
		fprintf(stderr, "Failed to load libgps from " LIBGPS_PATH ": %s\n", dlerror());
		return EXIT_FAILURE;
	}
	puts("Loaded libgps from " LIBGPS_PATH);

	libgpsd = dlopen(LIBGPSD_PATH, flags);
	if (NULL == libgpsd) {
		fprintf(stderr, "Failed to load libgpsd from " LIBGPSD_PATH ": %s\n", dlerror());
		return EXIT_FAILURE;
	}
	puts("Loaded libgpsd from " LIBGPSD_PATH);

	if (0 != dlclose(libgpsd)) {
		fprintf(stderr, "Failed to unload libgpsd: %s\n", dlerror());
		return EXIT_FAILURE;
	}
	puts("Unloaded libgpsd");

	if (0 != dlclose(libgps)) {
		fprintf(stderr, "Failed to unload libgps: %s\n", dlerror());
		return EXIT_FAILURE;
	}
	puts("Unloaded libgps");

	return EXIT_SUCCESS;
}