从Windows gui程序输出到命令行

Question

I have a win32 gui based exe which is GDI based -

The program accepts command line arguments when it starts, and I need a way to print out a message if the command line is incorrect.

At the moment, I am displaying an error message using MessageBox, and would like to know how to print out this error message if the user started the program from the dos command line. -

:)

ok this does what I want, but it requires me to press enter otherwise I dont see the current path displayed..

         void RedirectIOToConsole()
         {
         int hConHandle;
         FILE *fp;
         AttachConsole(-1);
         hConHandle=_open_osfhandle(GetStdHandle(STD_OUTPUT_HANDLE),_O_TEXT);
         fp=_fdopen(hConHandle,"w");
         fprintf(fp,"\ntesting\n");
         fflush(fp);
         _close(hConHandle);
         FreeConsole();
         }

Answer 1

Most applications that need to accomplish this will create a *.com version of their app (which will sit alongside the .exe). All shortcuts will point to the .exe, but if the user happens to type the name on a command line, then the .com version will end up executing (as CMD will search for .com files before .exe files) The .com version is often a thin wrapper which will invoke the .exe and wait for it to finish or utilize shared .dll files, but it exists purely so that output can be funneled to the proper console window and won't "release" it until the application finishes.

As an example, Microsoft's Visual Studio uses this approach:

C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE>dir devenv.*
 Volume in drive C has no label.
 Volume Serial Number is A482-59BA

 Directory of C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE

07/26/2012  05:05 PM             7,680 devenv.com
07/26/2012  07:08 PM           406,976 devenv.exe