Gdpfile.dll -

cl /LD /DEXPORTING_DLL gdpfile.c /Fe:gdpfile.dll so I can give you a precise, working implementation for your feature.

Compile with:

DLL_API int write_gdp_file(const char* filename, const double* data, int count) { // Write GDP data to custom file format return 1; // success } gdpfile.dll

DLL_API const char* get_last_error(void) { return last_error_msg; } cl /LD /DEXPORTING_DLL gdpfile

And the implementation:

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved) { return TRUE; } const double* data

DLL_API int read_gdp_file(const char* filename, double* data, int max_size) { // Your GDP file reading logic here return 0; // return number of values read }