Article: Q111753
Product(s): Microsoft C Compiler
Version(s): winnt:
Operating System(s):
Keyword(s): kbdocfix kbdocerr kbCRT kbVC
Last Modified: 26-JUL-2001
-------------------------------------------------------------------------------
The information in this article applies to:
- The C Run-Time (CRT), included with:
- *EDITOR Please do not choose this product*Microsoft Visual C++ 32-bit Edition* use 241, 265, 225, version 1.0
-------------------------------------------------------------------------------
SUMMARY
=======
The documentation in the Microsoft C "Run-Time Library Reference" for the assert
macro states that in Windows an assertion failure causes a pop-up box to be
displayed. This is stated similarly in the online help. Although this is true
for 16-bit Windows applications, under Win32 the macro just causes the
application to abort; no pop-up window is displayed.
The Visual C++ 2.0 documentation has the correct information.
MORE INFORMATION
================
The C run-time assert() macro was originally designed to display its diagnostic
message using console output. In the 16-bit Windows version of the C run time,
the macro was modified to use the Windows Graphical User Interface (GUI)
application programming interface (API). This was necessary because 16-bit
Windows does not support a console API.
Unlike 16-bit Windows, however, Win32 has both a GUI and console API set, and
therefore the assert() macro returns to its original form as a console output
macro.
It is possible to create a user-defined version of the assert() macro that
displays its diagnostic message in a pop-up window. The sample code provided
below shows one way of doing this:
Sample Code
-----------
/* Compile options needed: none
*/
#include <windows.h>
#include <stdio.h>
#include <process.h>
// Prototype for the function called by the assert macro.
void ShowAssertion(void * expr, void * filename, unsigned lineno);
// The following should all be on one line. It wraps around because
// of its length.
#define assert(exp) (void)( (exp) || (ShowAssertion(#exp, __FILE__,
__LINE__), 0) )
static char AssertString[] = "Expression %s, File %s, Line %d\n";
void ShowAssertion(void * expr, void * filename, unsigned lineno)
{
char buffer[256];
sprintf( buffer, AssertString, expr, filename, lineno );
MessageBox( NULL, buffer, "ASSERTION FAILED",
MB_OK | MB_ICONHAND | MB_TASKMODAL );
abort();
}
Additional query words: 2.00 debug runtime run time
======================================================================
Keywords : kbdocfix kbdocerr kbCRT kbVC
Technology : kbVCsearch kbAudDeveloper kbCRT
Version : winnt:
=============================================================================