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A sample of using dlopen library.
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#include <stdio.h> | |
#include <stdlib.h> | |
#include <string.h> | |
#include <dlfcn.h> | |
int main(int argc, char** argv) | |
{ | |
void *handle; | |
void (*func_print_name)(const char*); | |
if (argc != 2) { | |
fprintf(stderr, "Usage: %s animal_type\n", argv[0]); | |
return EXIT_FAILURE; | |
} | |
if (strcmp(argv[1], "dog") == 0) { | |
handle = dlopen("./libdog.so", RTLD_LAZY); | |
} else if (strcmp(argv[1], "cat") == 0) { | |
handle = dlopen("./libcat.so", RTLD_LAZY); | |
} else { | |
fprintf(stderr, "Error: unknown animal type: %s\n", argv[1]); | |
return EXIT_FAILURE; | |
} | |
if (!handle) { | |
/* fail to load the library */ | |
fprintf(stderr, "Error: %s\n", dlerror()); | |
return EXIT_FAILURE; | |
} | |
*(void**)(&func_print_name) = dlsym(handle, "print_name"); | |
if (!func_print_name) { | |
/* no such symbol */ | |
fprintf(stderr, "Error: %s\n", dlerror()); | |
dlclose(handle); | |
return EXIT_FAILURE; | |
} | |
func_print_name(argv[1]); | |
dlclose(handle); | |
return EXIT_SUCCESS; | |
} |
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#pragma once | |
void print_name(const char* type); |
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#include "animal.h" | |
#include <stdio.h> | |
void print_name(const char* type) | |
{ | |
printf("Tama is a %s.\n", type); | |
} |
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#include "animal.h" | |
#include <stdio.h> | |
void print_name(const char* type) | |
{ | |
printf("Pochi is a %s.\n", type); | |
} |
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app = dlopen_sample | |
lib = libcat.so libdog.so | |
CFLAGS = -Wall -ansi -pedantic | |
LDFLAGS = -ldl | |
all: $(app) $(lib) | |
lib%.so: %.c | |
$(CC) -shared -fPIC $(CFLAGS) -o $@ $< | |
clean: | |
$(RM) $(app) $(lib) | |
run: all | |
./$(app) cat | |
./$(app) dog | |
-./$(app) bear | |
$(lib): animal.h |
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