Debug C++ Runtime Component in a WP8 project - c++

Question

I've tried a lot of solutions, but none of them is working.
printf("Test : %d", 123);
std::cout << "Test" << 123 << std::endl;
...
Actually I've setup my project's debugger like this, I'm able to write in the console using OutputDebugStringA("Test"); but this function doesn't accept more than one parameter.
How can I print something like this : ("Test : %d", 123)?

Answer 1

Bogy's answer is on the right track but I don't like the allocation in GetWC which looks like a memory leak, and it uses unsafe functions, try this:
void Debug::Log(const wchar_t *format, ...)
{
wchar_t buffer[BUFFER_LENGTH];
va_list args;
va_start(args, format);
_vsnwprintf_s(buffer, BUFFER_LENGTH, _TRUNCATE, format, args);
va_end(args);
buffer[BUFFER_LENGTH - 1] = '\0'; //prevent buffer overflow
OutputDebugString(buffer);
}
Usage like:
Debug::Log(L"Hello %S\n", "sailor");

Answer 2

I found this code in a C++ training on Pluralsight that I am using for Windows 8 (you just say TRACE("Test : %d", 123); to use it):
#pragma once
#include <assert.h>
#define ASSERT assert
#ifdef _DEBUG
inline auto Trace(wchar_t const * format, ...) -> void
{
va_list args;
va_start(args, format);
wchar_t buffer[256];
ASSERT(-1 != _vsnwprintf_s(buffer, _countof(buffer) - 1, format, args));
va_end(args);
OutputDebugString(buffer);
}
#endif
struct Tracer
{
char const * m_filename;
unsigned m_line;
Tracer(char const * filename, unsigned const line) :
m_filename{ filename },
m_line{ line }
{
}
template <typename... Args>
auto operator()(wchar_t const * format, Args... args) const -> void
{
wchar_t buffer[256];
auto count = swprintf_s(buffer, L"%S(%d): ", m_filename, m_line);
ASSERT(-1 != count);
ASSERT(-1 != _snwprintf_s(buffer + count, _countof(buffer) - count, _countof(buffer) - count - 1, format, args...));
OutputDebugString(buffer);
}
};
#ifdef _DEBUG
#define TRACE Tracer(__FILE__, __LINE__)
#else
#define TRACE __noop
#endif

Answer 3

I've finally found this solution (here and here) :
Debug.cpp:
#pragma once
#include "pch.h"
#define BUFFER_LENGTH 1024
//char* to wchar_t*
const wchar_t *GetWC(const char *c)
{
const size_t cSize = strlen(c) + 1;
wchar_t* wc = new wchar_t[cSize];
mbstowcs(wc, c, cSize);
return wc;
}
void Debug::Log(const char *format, ...)
{
char buffer[BUFFER_LENGTH];
va_list args;
va_start(args, format);
vsnprintf(buffer, BUFFER_LENGTH, format, args);
va_end(args);
buffer[BUFFER_LENGTH - 1] = '\0'; //prevent buffer overflow
OutputDebugString(GetWC(buffer));
}
Debug.h:
class Debug{
public:
static void Log(const char *format, ...);
};
We can use it like printf function:
Debug::Log("Test : %d", 123);