Microsoft KB Archive/107432

= PRB: Inline Assembly C++ Function May Need Return Statement =

Article ID: 107432

Article Last Modified on 12/2/2003

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APPLIES TO


 * Microsoft C/C++ Professional Development System 7.0
 * Microsoft Visual C++ 1.0 Professional Edition
 * Microsoft Visual C++ 1.5 Professional Edition
 * Microsoft Visual C++ 2.0 Professional Edition

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This article was previously published under Q107432



SYMPTOMS
C++ functions containing inline assembly routines that store the return value in the AX register may need a return statement added to the function. If the function does not have a return statement, the following error is generated:

C2561: 'function name' function must return a value



RESOLUTION
To resolve this error, create a temporary variable and move the AX register to this variable for the return statement. This will work around the C++ type-checking syntax. If you are using C++ version 8.0 that ships with Visual C++ for Windows NT, then the EAX register must be used instead.

Sample Code
/* Compile options needed: none

int func(void) { //int a;         //Remove this comment to eliminate the error. __asm {   mov ax, 02h ;mov a, ax        //Remove this comment to eliminate the error. } //return a;         //Remove this comment to eliminate the error. }

void main(void) { int a;  a = func; }

Additional query words: 7.00 8.00 8.00c 9.00 1.00 1.50 2.00

Keywords: kbprb KB107432

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