Microsoft KB Archive/167995

= FIX: Calling a Function Returning double May Not Pop FPU Stack =

Article ID: 167995

Article Last Modified on 7/5/2005

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APPLIES TO


 * Microsoft Visual C++ 5.0 Enterprise Edition
 * Microsoft Visual C++ 5.0 Professional Edition

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This article was previously published under Q167995



SYMPTOMS
When you call a function that returns a double, from within a conditional, and build with /Od, the compiler does not pop the Coprocessor stack. This may cause a floating point stack overflow (0xc0000092), or later calculations involving the FPU to evaluate to -1.#IND00. The sample below demonstrates a form of this bug.



RESOLUTION
Enable global optimizations (/Og).



STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug has been corrected in Visual Studio 97 Service Pack 1.

For additional information about the Visual Studio 97 Service Pack 1, please see the following article in the Microsoft Knowledge Base:

170365 INFO: Visual Studio 97 Service Packs - What, Where, and Why



Sample Code
// Compile options needed: /Od #include   #include    double func {    return 1.0; }  void main {     int i;      double d=2.0; // uncomment the next line to unmask exception //_controlfp(_EM_OVERFLOW, _MCW_EM ); for( i = 0; i < 10; i++ ) {        if( func ); }     // outputs -1.#IND00 printf("%f",d+d); }

Additional query words: STATUS_FLOAT_STACK_CHECK EXCEPTION_FLT_STACK_CHECK indefinite

Keywords: kbbug kbfix kbvs97sp1fix kbcode kbcompiler KB167995

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