Question

I am using a macro to do simple logging on different platforms. Here’s some of what I use on android:

#include <android/log.h>
#define __ENGINE_LOG_INFO(msg, argptr) __android_log_vprint(ANDROID_LOG_INFO, __ENGINE_LOG_TAG, msg, argptr);

And here’s the corresonding I’ve tried on windows:

#elif defined _WIN32 || _WIN64
#include <stdarg.h>
#include <stdio.h>
#define __ENGINE_LOG_INFO(msg, argptr)  printf ("%s:%s",__ENGINE_LOG_TAG,"DEBUG:"); printf(msg, argptr); printf("\n");

The macro is invoked in this function:

void LogManagerImpl::LogInfo(const char* msg, ...)
{
    va_list argptr;
    va_start(argptr, msg);
    __ENGINE_LOG_INFO(msg, argptr);
    va_end(argptr);
}

For example, I use it like this:

engine->GetLogger()->LogInfo("TEST: MemoryManagerTest:AllocateWithMemPool: Loop time: %d msec", timeStop - timeStart);

This works fine on Android, but for some reason it seems to print bogus values in Windows (it is the exact same value everytime – a very big value). I am starting to think it looks like an address, but I’m not sure why its not working. Any ideas?

Answer 1

You want to use vprintf(msg, argptr); rather than printf(msg, argptr); in your windows version. The vprintf() function was designed to work with a va_list type as the container for the actual argument values that will be matched against the values indicated in the input character string, where-as printf() was not.