Call C methods from C++/Java/C# code?

An example of calling C from C++. Save this C function in a file called a.c:

int f() {
   return 42;
}

and compile it:

gcc -c a.c

which will produce a file called a.o. Now write a C++ program in a file called main.cpp:

#include <iostream>
extern "C" int f();

int main() {
   std::cout << f() << std::endl;
}

and compile and link with:

g++ main.cpp a.o -o myprog

which will produce an execuatable called myprog which prints 42 when run.

To Call C Methods In Java...

there a Keyword "native" in Which You can write machine-dependent C code and invoke it from Java....

Basically it creates a DLL file..then u have to load it in ur program...

a nice example here....

To call C methods from Java, there are multiple options, including:

• JNA - Java Native Access. Free. Easy to use. Hand-declaration of Java classes and interfaces paralleling existing C structs and functions. Slower than JNI - by a few hundred nanoseconds per call.
• JNI - Java Native Interface. Free. Fastest option. Requires a layer of native glue code between your Java code and the native functions you want to call.
• JNIWrapper - Commercial product, similar to JNA.

To call C/C++ from Java, also give a look at BridJ (it's like JNA with C++ and better performance).