Tuesday, August 18, 2009

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Wednesday, August 12, 2009

Use Extern function in a library (C++)

Here is an example of usage of extern function in a (Static) Library.

stw.h:

#ifdef __cplusplus
extern "C"
#endif
void show_the_world(void);

stw.cpp:

#include 
#include "stw.h"
using namespace std;

extern "C" void show_the_world() {
cout
<< "Hello, world!\n";
}

Build the library:

$ g++ -c stw.cpp -o stw.cpp -O0 -g
$ ar rcs stw
.a stw.o

Using the library from a C application:

myapp.c:

#include "stw.h"

int main() {
show_the_world
();
return 0;
}

Building the C application:

$ gcc -o myapp myapp.c stw.a -lstdc++ -g -O0
$
./myapp
Hello, world!
$