sayhello.c


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

int main(int argc, const char *argv[]) {
	int i;
#ifdef DISABLE_PLUGINS
	sayhello();
#else
	if (argc < 2)
		errx(1, "usage: sayhello PLUGIN...");

	for (i=1; i<argc; i++) {
		const char *plugin = argv[i];
		void (*sayhello)(void);
		void *handle = dlopen(plugin, RTLD_NOW | RTLD_LOCAL);

		if (handle == NULL) {
			warn("%s", plugin);
			continue;
		}
		dlerror(); /* clear existing error */

		/* get the "sayhello" function from plugin */
		sayhello = (void (*)(void)) dlsym(handle, "sayhello");
		sayhello();

		dlclose(handle);
	}
#endif

	return 0;
}