luser · January 9, 2018 14:23
diff --git a/.gitignore b/.gitignore
 *~
 libcallback.so
 weak
diff --git a/callback.c b/callback.c
 #include <stdio.h>

 void callback() {
  printf("Hello from libcallback!\n");
 }
diff --git a/Makefile b/Makefile
 all: weak libcallback.so

 weak: weak.c
 	$(CC) -o $@ $<

 libcallback.so: callback.c
 	$(CC) -o $@ $< -shared
diff --git a/weak.c b/weak.c
 void __attribute__((weak)) callback();

 int main(int argc, char** argv) {
  if (callback) {
    callback();
  }
  return 0;
 }
	#include <stdio.h>

	void callback() {
	printf("Hello from libcallback!\n");
	}
	void __attribute__((weak)) callback();

	int main(int argc, char** argv) {
	if (callback) {
	callback();
	}
	return 0;
	}