Define a wrapper around a global function

Used in: User defined namespace scope

Define access to a library function you want to write a wrapper for, for example for checking parameters or inject hard-to-test error situations.

	Note
	CRPCUT_WRAP_V_FUNC uses dlopen() and dlsym() to get access to the library function. This means you can only access functions in a shared library, and also that functions used by dlopen() and dlsym() are very tricky to get access to. crpcut already provides wrappers for the heap (See crpcut::heap.)

	Caution
	Do not expand CRPCUT_WRAP_V_FUNC in global scope, or you will be unable to make a wrapper, since the expansion will create a new function with the same name.

Example: The test program

     
     #include <crpcut.hpp>
     
     extern "C"
     {
     #include <stdio.h>
     #include <string.h>
     }
     
     namespace original {
       CRPCUT_WRAP_V_FUNC(libc,
                          exit,
                          __attribute__ ((noreturn)) void,
                          (int code),
                          (code))
     }
     
     int expected_code = 0;
     extern "C"
     {
       __attribute__ ((noreturn)) void exit(int code) throw ()
       {
         if (expected_code != code)
           {
             FAIL << "exit() called with " << code <<
               " when " << expected_code << " was expected";
           }
         original::exit(code);
       }
     }
     
     TEST(wrapped_exit_succeeds, EXPECT_EXIT(ANY_CODE))
     {
       expected_code = 3;
       exit(3);
     }
     
     TEST(wrapped_exit_fails, EXPECT_EXIT(ANY_CODE))
     {
       expected_code = 3;
       exit(0);
     }
     
     int main(int argc, char *argv[])
     {
       return crpcut::run(argc, argv);
     }

        

reports one failed test:

     FAILED!: wrapped_exit_fails
     phase="running"  --------------------------------------------------------------
     samples/wrap_v_func.cpp:51
     exit() called with 0 when 3 was expected
     -------------------------------------------------------------------------------
     ===============================================================================
     2 test cases selected
     
                    Sum   Critical   Non-critical
     PASSED   :       1          1              0
     FAILED   :       1          1              0

        

See crpcut::libs for details.

See also CRPCUT_WRAP_FUNC(lib, func, rv, param_list, param_call) for functions returning a value, EXPECT_EXIT(num, action?), ANY_CODE and FAIL