How to use function from static library if I don't have header file

Question

Is it a way to use function from static lib, if I don't have header file, only *.a file, but I know function signature?

Answer 1

Yes, if you know the function signature

Just write the function signature before calling it, as:

void f(int); //it is as if you've included a header file  //then call it f(100); 

All you need to do is : link the slib.a to the program.

Also, remember that, if the static library is written in C and has been compiled with C compiler, then you've to use extern "C" when writing the function signature (if you program in C++), as:

extern "C" void f(int); //it is as if you've included a header file  //then call it f(100); 

Alternatively, if you've many functions, then you can group them together as:

extern "C"  {    void f(int);     void g(int, int);     void h(int, const char*); }  

You may prefer writing all the function signatures in a namespace so as to avoid any possible name-collisions:

namespace capi {   extern "C"    {     void f(int);      void g(int, int);      void h(int, const char*);   }  }  //use them as:  capi::f(100);  capi::g(100,200);  capi::h(100,200, "string");  

Now you can write all these in a header file so that you could include the header file in your .cpp files (as usual), and call the function(s) (as usual).

Hope that helps.

Answer 2

The easiest way: Write the signature in a header file, include it and link against the library.