How to write to the Output window in Visual Studio

Question

Which function should I use to output text to the  Output  window in Visual Studio   I tried printf   but it doesn t show up

User · Answer

Use OutputDebugString instead of afxDump.

Example:

#define _TRACE_MAXLEN 500

#if _MSC_VER >= 1900
#define _PRINT_DEBUG_STRING(text) OutputDebugString(text)
#else // _MSC_VER >= 1900
#define _PRINT_DEBUG_STRING(text) afxDump << text
#endif // _MSC_VER >= 1900

void MyTrace(LPCTSTR sFormat, ...)
{
    TCHAR text[_TRACE_MAXLEN + 1];
    memset(text, 0, _TRACE_MAXLEN + 1);
    va_list args;
    va_start(args, sFormat);
    int n = _vsntprintf(text, _TRACE_MAXLEN, sFormat, args);
    va_end(args);
    _PRINT_DEBUG_STRING(text);
    if(n <= 0)
        _PRINT_DEBUG_STRING(_T("[...]"));
}

User · Answer

define WIN32 LEAN AND MEAN  include  lt Windows h gt   wstring outputMe   L can    L  concatenate n   OutputDebugString outputMe c str

User · Answer

If this is for debug output then OutputDebugString is what you want  A useful macro      define DBOUT  s                                                   std  ostringstream os           os   lt  lt  s                         OutputDebugString  os  str   c str             This allows you to say things like   DBOUT   The value of x is    lt  lt  x      You can extend this using the   LINE   and   FILE   macros to give even more information   For those in Windows and wide character land    include  lt Windows h gt   include  lt iostream gt   include  lt sstream gt     define DBOUT  s                                                   std  wostringstream os           os   lt  lt  s                         OutputDebugStringW  os  str   c str

User · Answer

Even though OutputDebugString indeed prints a string of characters to the debugger console  it s not exactly like printf with regard to the latter being able to format arguments using the   notation and a variable number of arguments  something OutputDebugString does not do   I would make the case that the  RPTFN macro  with  CRT WARN argument at least  is a better suitor in this case -- it formats the principal string much like printf  writing the result to debugger console   A minor  and strange  in my opinion  caveat with it is that it requires at least one argument following the format string  the one with all the   for substitution   a limitation printf does not suffer from   For cases where you need a puts like functionality -- no formatting  just writing the string as-is -- there is its sibling  RPTF0  which ignores arguments following the format string  another strange caveat   Or OutputDebugString of course   And by the way  there is also everything from  RPT1 to  RPT5 but I haven t tried them  Honestly  I don t understand why provide so many procedures all doing essentially the same thing

User · Answer

Use the OutputDebugString function or the TRACE macro  MFC  which lets you do printf-style formatting   int x   1  int y   16  float z   32 0  TRACE   This is a TRACE statement n         TRACE   The value of x is  d n   x    TRACE   x    d and y    d n   x  y    TRACE   x    d and y    x and z    f n   x  y  z

User · Answer

Useful tip - if you use   FILE   and   LINE   then format your debug as    file line   Your output here    then when you click on that line in the output window Visual Studio will jump directly to that line of code  An example    include  lt Windows h gt   include  lt iostream gt   include  lt sstream gt   void DBOut const char  file  const int line  const WCHAR  s        std  wostringstream os       os   lt  lt  file  lt  lt       lt  lt  line  lt  lt             os   lt  lt  s      OutputDebugStringW os  str   c str         define DBOUT s        DBOut   FILE      LINE    s    I wrote a blog post about this so I always knew where I could look it up  https   windowscecleaner blogspot co nz 2013 04 debug-output-tricks-for-visual-studio html

User · Answer

OutputDebugString function will do it   example code      void CClass  Output const char  szFormat             char szBuff 1024       va list arg      va start arg  szFormat        vsnprintf szBuff  sizeof szBuff   szFormat  arg       va end arg        OutputDebugString szBuff

[c++] How to write to the Output window in Visual Studio?

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