Using a integer for OutputDebugString in VS2017 - c++

Question

I've been searching around on the web for a while on how to output a integer or optionally a float using OutputDebugString().
It would be easier if i could write my debug data straight to the console from my external executable using this command. However i only got it to work with a const char.
The solutions i found were outdated i tried copy and pasting the code straight from the web but didn't work. Even after modifying the code i couldn't get it to typecast correctly.
Is there anyone that could help me typecast something into the OutputDebugString as clean as possible, it's for debugging purposes only so i rather keep the code short and easily readable than having a more complex and clunky typecast IF that is possible. Many thanks!

Answer 1

Provided alternatively solution. The function below encapsulates OutputDebugString that can accept formatted arguments.
#include <vector>
#include <string>
void DbgMsg(const char * zcFormat, ...)
{
// initialize use of the variable argument array
va_list vaArgs;
va_start(vaArgs, zcFormat);
// reliably acquire the size
// from a copy of the variable argument array
// and a functionally reliable call to mock the formatting
va_list vaArgsCopy;
va_copy(vaArgsCopy, vaArgs);
const int iLen = std::vsnprintf(NULL, 0, zcFormat, vaArgsCopy);
va_end(vaArgsCopy);
// return a formatted string without risking memory mismanagement
// and without assuming any compiler or platform specific behavior
std::vector<char> zc(iLen + 1);
std::vsnprintf(zc.data(), zc.size(), zcFormat, vaArgs);
va_end(vaArgs);
std::string strText(zc.data(), iLen);
OutputDebugStringA(strText.c_str());
}
For example, the code below shows how to print an integer variable by OutputDebugString through DbgMsg().
int foo=12;
DbgMsg(" foo=%d", foo);

Answer 2

OutputDebugString can only take strings, if you want formatted output you will have to do that yourself before feeding it to OutputDebugString. If you are using MSVC I suggest that you use _CrtDbgReport or _CrtDbgReportW. With recent versions of MSVC that support variadic macros I use the following:
#if !defined(_RPTW)
#if defined(_DEBUG)
#define _RPTW(pszFmt, ...) _CrtDbgReportW(_CRT_WARN, NULL, __LINE__, NULL, (pszFmt), __VA_ARGS__)
#define _RPTW_(dest, fmt, ...) _CrtDbgReportW((dest), NULL, __LINE__, NULL, (pszFmt), __VA_ARGS__)
#else
#define _RPTW(pszFmt, ...)
#define _RPTW(dest, pszFmt)
#endif
#endif // #if !defined(_RPTW)
#if !defined(_RPTA)
#if defined(_DEBUG)
#define _RPTA(pszFmt, ...) _CrtDbgReport(_CRT_WARN, NULL, __LINE__, NULL, (pszFmt), __VA_ARGS__)
#define _RPTA_(dest, fmt, ...) _CrtDbgReport((dest), NULL, __LINE__, NULL, (pszFmt), __VA_ARGS__)
#else
#define _RPTA(pszFmt, ...)
#define _RPTA_(dest, pszFmt)
#endif
#endif // #if !defined(_RPTA)
#if !defined(_RPTT)
#if defined(_UNICODE)
#define _RPTT _RPTW
#define _RPTT_ _RPTW_
#else
#define _RPTT _RPTA
#define _RPTT_ _RPTA_
#endif
#endif // #if !defined(_RPTT)
The second forms allow providing a different level of report (_CRT_ASSERT or c_CRT_ERROR instead of _CRT_WARN)

Answer 3

I would recommend to use sprintf like that:
// issues with the int x, let's output and look at it in DebugView
char msg[255] = {0};
sprintf(msg, ">> Watch out x=%d\n", x);
OutputDebugString(msg);
Maybe I did not understand the question, but that's how I quickly dump integers. And to be honest I do not know these MACROS which SoronelHaetir listed but indeed you've got to format yourself. So I Hope this helps and is rather straight forward.