GetExceptionCode

This function retrieves a code that identifies the type of exception that occurred. GetExceptionCode can be called only from within the filter expression or exception-handler block of a try-except exception handler.

At a Glance

Syntax

DWORD GetExceptionCode(void);

Return Values

The return value identifies the type of exception. Following are the exception codes likely to occur due to common programming errors:

EXCEPTION_ACCESS_VIOLATION

The thread attempted to read from or write to a virtual address for which it does not have the appropriate access.

EXCEPTION_BREAKPOINT

A breakpoint was encountered.

EXCEPTION_DATATYPE_MISALIGNMENT

The thread attempted to read or write data that is misaligned on hardware that does not provide alignment. For example, 16-bit values must be aligned on 2-byte boundaries, 32-bit values on 4-byte boundaries, and so on.

EXCEPTION_SINGLE_STEP

A trace trap or other single-instruction mechanism signaled that one instruction has been executed.

EXCEPTION_ARRAY_BOUNDS_EXCEEDED

The thread attempted to access an array element that is out of bounds, and the underlying hardware supports bounds checking.

EXCEPTION_FLT_DENORMAL_OPERAND

One of the operands in a floating-point operation is denormal. A denormal value is one that is too small to represent as a standard floating-point value.

EXCEPTION_FLT_DIVIDE_BY_ZERO

The thread attempted to divide a floating-point value by a floating-point divisor of zero.

EXCEPTION_FLT_INEXACT_RESULT

The result of a floating-point operation cannot be represented exactly as a decimal fraction.

EXCEPTION_FLT_INVALID_OPERATION

This exception represents any floating-point exception not included in this list.

EXCEPTION_FLT_OVERFLOW

The exponent of a floating-point operation is greater than the magnitude allowed by the corresponding type.

EXCEPTION_FLT_STACK_CHECK

The stack overflowed or underflowed as the result of a floating-point operation.

EXCEPTION_FLT_UNDERFLOW

The exponent of a floating-point operation is less than the magnitude allowed by the corresponding type.

EXCEPTION_INT_DIVIDE_BY_ZERO

The thread attempted to divide an integer value by an integer divisor of zero.

EXCEPTION_INT_OVERFLOW

The result of an integer operation caused a carry out of the most significant bit of the result.

EXCEPTION_PRIV_INSTRUCTION

The thread attempted to execute an instruction whose operation is not allowed in the current machine mode.

EXCEPTION_NONCONTINUABLE_EXCEPTION

The thread attempted to continue execution after a noncontinuable exception occurred.

Remarks

The Excpt.h file has to be explicitly included in order to use GetExceptionCode.

The GetExceptionCode function can be called only from within the filter expression or exception-handler block of a try-except statement. The filter expression is evaluated if an exception occurs during execution of the try block, and it determines whether the except block is executed.

The filter expression can invoke a filter function. The filter function cannot call GetExceptionCode. However, the return value of GetExceptionCode can be passed as a parameter to a filter function. The return value of the GetExceptionInformation function can also be passed as a parameter to a filter function. GetExceptionInformation returns a pointer to a structure that includes the exception-code information.

The following code example shows the structure of a try-except statement.

try 
{ 
 
    // try block 
 
} 
except ( FilterFunction(GetExceptionCode() ) 
{ 
 
    // exception handler block 
 
} 
 

In the case of nested try-except statements, each statement’s filter expression is evaluated until one is evaluated as EXCEPTION_EXECUTE_HANDLER or EXCEPTION_CONTINUE_EXECUTION. Each filter expression can invoke GetExceptionCode to get the exception code.

The exception code returned is the code generated by a hardware exception, or the code specified in the RaiseException function for a software-generated exception.

When handling the breakpoint exception, it is important to increment the instruction pointer in the context record to continue from this exception.

See Also

GetExceptionInformation