External c/c++

Community Forums/Monkey2 Talk/External c/c++

impixi

(Posted 2016) [#1]

I'm trying to code an example for Extern and I can't seem to make it work.. The following compiles in Monkey2 but I see the following error in the console:

/exte1.buildv002/build_cache/desktop_debug_windows/exte1_0exte1.cpp.o: In function `Z6bbMainv':
/exte1.buildv002/build_cache/desktop_debug_windows/exte1_exte1.cpp:17: undefined reference to `GetSysSeed()'

I've examined the generated c++ files and they don't seem to incorporate some of my c code. Leads me to believe I'm missing something obvious, though I can't see what it is. Comparing my own source files to those of the monkey2 module source, they *seem* to follow the same format...

Here are my source files:

utils.h

#if _WIN32
	#include <windows.h>
#else
	#include <time.h>
#endif

unsigned long GetSysSeed(void);

utils.c

#include "utils.h"

unsigned long GetSysSeed(void)
{
	#if _WIN32
		return (unsigned long)GetTickCount();
	#else
		struct timespec tm;
		clock_gettime(CLOCK_MONOTONIC, &tm);
		return (unsigned long)tm.tv_nsec;
	#endif
}

utils.monkey2

Namespace utils

#Import "utils.h"
#Import "utils.c"

Extern

Function GetSysSeed:ULong()

exte1.monkey2

'External Code Access Simple Example

#Import "utils.monkey2"
#Import "<std.monkey2>"

Using std
Using utils

Function Main()
	Local seed := GetSysSeed()
	Print seed
End

Any ideas?

Danilo

(Posted 2016) [#2]

Try renaming utils.c to utils.cpp - it finds the function here with .cpp file.

Maybe you need to use ' extern "C“ ' for C functions in .c files (because MX2 is C++, not C):

extern "C" unsigned long GetSysSeed(void);

On Mac OS X I get another error (but compiles when out-commenting that part):

utils.cpp:9:17: error: use of undeclared identifier 'CLOCK_MONOTONIC'
                clock_gettime(CLOCK_MONOTONIC, &tm);
                              ^
1 error generated.

EDIT:
Verified: With .c file, change utils.h to the following:

#if _WIN32
	#include <windows.h>
#else
	#include <time.h>
#endif


#ifdef __cplusplus
  extern "C" {
#endif

unsigned long GetSysSeed(void);

#ifdef __cplusplus
  } // end extern "C"
#endif

impixi

(Posted 2016) [#3]

Ah, thanks!

And it looks like I need to write an additional branch for __APPLE__, since clock_gettime() is not implemented in Mac OS...