_CrtSetReportMode

Visual Studio 6.0

Specifies the general destination(s) for a specific report type generated by _CrtDbgReport (debug version only).

int _CrtSetReportMode( int reportType, int reportMode );

Routine Required Header Compatibility
_CrtSetReportMode <crtdbg.h> Win NT, Win 95

For additional compatibility information, see Compatibility in the Introduction.

Libraries

LIBCD.LIB Single thread static library, debug version
LIBCMTD.LIB Multithread static library, debug version
MSVCRTD.LIB Import library for MSVCRTD.DLL, debug version

Return Value

Upon successful completion, _CrtSetReportMode returns the previous report mode(s) for the report type specified in reportType. If an error occurs, the report mode(s) for reportType are not modified and_CrtSetReportMode returns –1.

Parameters

reportType

Report type: _CRT_WARN, _CRT_ERROR, _CRT_ASSERT

reportMode

New report mode(s) for reportType, see the table in the Remarks section

Remarks

_CrtSetReportMode is used in conjunction with the _CrtSetReportFile function to define the destination(s) for a specific report type generated by _CrtDbgReport. If _CrtSetReportMode and _CrtSetReportFile are not called to define the reporting method(s) for a specific report type, then _CrtDbgReport generates the report type using default destinations: Assertion failures and errors are directed to a debug message window, warnings from Windows applications are sent to the debugger, and warnings from console applications are directed to stderr. When _DEBUG is not defined, calls to _CrtSetReportMode are removed during preprocessing.

The following table lists the report types defined in CRTDBG.H.

Report Type Description
_CRT_WARN Warnings, messages, and information that does not need immediate attention.
_CRT_ERROR Errors, unrecoverable problems, and issues that require immediate attention.
_CRT_ASSERT Assertion failures (asserted expressions that evaluate to FALSE).

The _CrtSetReportMode function assigns the new report mode specified in reportMode to the report type specified in reportType and returns the previously defined report mode for reportType. The following table lists the available choices for reportMode and the resulting behavior of _CrtDbgReport. These options are defined as bit-flags in CRTDBG.H.

Report Mode _CrtDbgReport Behavior
_CRTDBG_MODE_DEBUG Writes the message to an output debug string.
_CRTDBG_MODE_FILE Writes the message to a user-supplied file handle. _CrtSetReportFile should be called to define the specific file or stream to use as the destination.
_CRTDBG_MODE_WNDW Creates a message box to display the message along with the Abort, Retry, and Ignore buttons.
_CRTDBG_REPORT_MODE It is not called, and the report mode for reportType is not modified. _CrtSetReportMode simply returns the current report mode for reportType.

Each report type may be reported using one, two, or three modes, or no mode at all. Therefore, it is possible to have more than one destination defined for a single report type. For example, the following code fragment causes assertion failures to be sent to both a debug message window and to stderr:

_CrtSetReportMode( _CRT_ASSERT, _CRTDBG_MODE_FILE | _CRTDBG_MODE_WNDW );
_CrtSetReportFile( _CRT_ASSERT, _CRTDBG_FILE_STDERR );

In addition, the reporting mode(s) for each report type can be separately controlled. For example, it is possible to specify that a reportType of _CRT_WARN be sent to an output debug string, while _CRT_ASSERT be displayed using a a debug message window and sent to stderr, as illustrated above.

For more information about defining the report mode(s) and file for a specific report type, see _CrtDbgReport, _CrtSetReportFile and the section Debug Reporting Functions of the C Run-Time Library.

Example

/*
 * REPORT.C:
 * In this program, calls are made to the _CrtSetReportMode,
 * _CrtSetReportFile, and _CrtSetReportHook functions.
 * The _ASSERT macros are called to evaluate their expression.
 * When the condition fails, these macros print a diagnostic message
 * and call _CrtDbgReport to generate a debug report and the
 * client-defined reporting function is called as well.
 * The _RPTn and _RPTFn group of macros are also exercised in
 * this program, as an alternative to the printf function.
 * When these macros are called, the client-defined reporting function
 * takes care of all the reporting - _CrtDbgReport won't be called.
 */

#include <stdio.h>
#include <string.h>
#include <malloc.h>
#include <crtdbg.h>

/*
 * Define our own reporting function.
 * We'll hook it into the debug reporting
 * process later using _CrtSetReportHook.
 *
 * Define a global int to keep track of
 * how many assertion failures occur.
 */
int gl_num_asserts=0;
int OurReportingFunction( int reportType, char *userMessage, int *retVal )
{
   /*
    * Tell the user our reporting function is being called.
    * In other words - verify that the hook routine worked.
    */
   fprintf("Inside the client-defined reporting function.\n", STDOUT);
   fflush(STDOUT);

   /*
    * When the report type is for an ASSERT,
    * we'll report some information, but we also
    * want _CrtDbgReport to get called -
    * so we'll return TRUE.
    *
    * When the report type is a WARNing or ERROR,
    * we'll take care of all of the reporting. We don't
    * want _CrtDbgReport to get called -
    * so we'll return FALSE.
    */
   if (reportType == _CRT_ASSERT)
   {
      gl_num_asserts++;
      fprintf("This is the number of Assertion failures that have occurred: %d \n", gl_num_asserts, STDOUT);
      fflush(STDOUT);
      fprintf("Returning TRUE from the client-defined reporting function.\n", STDOUT);
      fflush(STDOUT);
      return(TRUE);
   } else {
      fprintf("This is the debug user message: %s \n", userMessage, STDOUT);
      fflush(STDOUT);
      fprintf("Returning FALSE from the client-defined reporting function.\n", STDOUT);
      fflush(STDOUT);
      return(FALSE);
   }

   /*
    * By setting retVal to zero, we are instructing _CrtDbgReport
    * to continue with normal execution after generating the report.
    * If we wanted _CrtDbgReport to start the debugger, we would set
    * retVal to one.
    */
   retVal = 0;
}

int main()
{
      char *p1, *p2;

   /*
    * Hook in our client-defined reporting function.
    * Every time a _CrtDbgReport is called to generate
    * a debug report, our function will get called first.
    */
   _CrtSetReportHook( OurReportingFunction );

   /*
    * Define the report destination(s) for each type of report
    * we are going to generate.  In this case, we are going to
    * generate a report for every report type: _CRT_WARN,
    * _CRT_ERROR, and _CRT_ASSERT.
    * The destination(s) is defined by specifying the report mode(s)
    * and report file for each report type.
    * This program sends all report types to STDOUT.
    */                                            
   _CrtSetReportMode(_CRT_WARN, _CRTDBG_MODE_FILE);
   _CrtSetReportFile(_CRT_WARN, _CRTDBG_FILE_STDOUT);
   _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_FILE);
   _CrtSetReportFile(_CRT_ERROR, _CRTDBG_FILE_STDOUT);
   _CrtSetReportMode(_CRT_ASSERT, _CRTDBG_MODE_FILE);
   _CrtSetReportFile(_CRT_ASSERT, _CRTDBG_FILE_STDOUT);

   /*
    * Allocate and assign the pointer variables
    */
   p1 = malloc(10);
   strcpy(p1, "I am p1");
   p2 = malloc(10);
   strcpy(p2, "I am p2");

   /*
    * Use the report macros as a debugging
    * warning mechanism, similar to printf.
    *
    * Use the assert macros to check if the
    * p1 and p2 variables are equivalent.
    *
    * If the expression fails, _ASSERTE will
    * include a string representation of the
    * failed expression in the report.
    *
    *  _ASSERT does not include the
    * expression in the generated report.
    */
   _RPT0(_CRT_WARN, "\n\n Use the assert macros to evaluate the expression p1 == p2.\n");
   _RPTF2(_CRT_WARN, "\n Will _ASSERT find '%s' == '%s' ?\n", p1, p2);
   _ASSERT(p1 == p2);

   _RPTF2(_CRT_WARN, "\n\n Will _ASSERTE find '%s' == '%s' ?\n", p1, p2);
   _ASSERTE(p1 == p2);

   _RPT2(_CRT_ERROR, "\n \n '%s' != '%s'\n", p1, p2);

   free(p2);
   free(p1);

   return 0;
}

Output

Inside the client-defined reporting function.
This is the debug user message: Use the assert macros to evaluate the expression p1 == p2
Returning FALSE from the client-defined reporting function.
Inside the client-defined reporting function.
This is the debug user message: dbgmacro.c(54) : Will _ASSERT find 'I am p1' == 'I am p2' ?
Returning FALSE from the client-defined reporting function.
Inside the client-defined reporting function.
This is the number of Assertion failures that have occurred: 1
Returning TRUE from the client-defined reporting function.
dbgmacro.c(55) : Assertion failed
Inside the client-defined reporting function.
This is the debug user message: dbgmacro.c(57) : Will _ASSERTE find 'I am p1' == 'I am p2' ?
Returning FALSE from the client-defined reporting function.
Inside the client-defined reporting function.
This is the number of Assertion failures that have occurred: 2
Returning TRUE from the client-defined reporting function.
dbgmacro.c(58) : Assertion failed: p1 == p2
Inside the client-defined reporting function.
This is the debug user message: 'I am p1' != 'I am p2'
Returning FALSE from the client-defined reporting function.

Debug Functions

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