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Designates a function as the handler for reporting run-time error checks (RTCs).

_RTC_error_fnW _RTC_SetErrorFuncW(
   _RTC_error_fnW function 


The address of the function that will handle run-time error checks.

The previously defined error function. If there is no previously defined function, returns NULL.

Use only _RTC_SetErrorFuncW in new code. _RTC_SetErrorFunc is only included in the library for backward compatibility.

The _RTC_SetErrorFuncW callback applies only to the component that it was linked in, but not globally.

Make sure that the address you pass to _RTC_SetErrorFuncW is that of a valid error handling function.

If an error has been assigned a type of –1 with _RTC_SetErrorType, the error handler function is not called.

Before you can call this function, you must first call one of the run-time error check initialization functions; see Using Run-Time Checks without the C Run-Time Library

_RTC_error_fnW is defined as follows:

typedef int (__cdecl *_RTC_error_fnW)(int errorType, const wchar_t *filename, int linenumber, const wchar_t *moduleName, const wchar_t *format, ...);



The type of error specified by _RTC_SetErrorType.


The source file where the failure occurred or null if no debug information is available.


The line in filename where the failure occurred or 0 if no debug information is available.


The DLL or executable name where the failure occurred.


printf style string to display an error message, using the remaining parameters. The first argument of the VA_ARGLIST is the RTC Error number that occurred.

For an example of using _RTC_error_fnW, see Customizing CRT Run-Time Error Checking.


Required header



For more information, see Compatibility.


All versions of the C run-time libraries.

Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.

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