INFO: Must Use Prototype Before Intrinsic or Function Pragmas

• The Microsoft C/C++ Compiler (CL.EXE) included with: - Microsoft C for MS-DOS, versions 6.0, 6.0a, 6.0ax - Microsoft C/C++ for MS-DOS, version 7.0 - Microsoft Visual C++ for Windows, versions 1.0, 1.5, 1.51, 1.52 - Microsoft Visual C++ 32-bit Edition, versions 1.0, 2.0, 2.1, 4.0, 5.0

SUMMARY

There are a number of C Run-time routines that have both a function version and an intrinsic version. If the following statement is used in an application to force use of the function version:

   #pragma function( a_CFunction )

   error C2164: 'a_CFunction': intrinsic was not declared.

   #pragma intrinsic( a_CFunction )

MORE INFORMATION

When you don't use the /Oi or /Ox option, you need to declare a function prototype before you can use the function or intrinsic pragmas. For example, to properly use the memcpy function in the Sample Code below, either STRING.H or MEMORY.H must be included. Consult the C Run-time documentation for the appropriate header (.H) file to include.

For more information about #pragma intrinsic or C Run-time functions that have intrinsic versions, consult the documentation provided with your Microsoft compiler or development environment.

Sample Code

   /* Compile options needed: none
   */

   #pragma function( memcpy )

   char s1[] = "string";
   char s2[10];

   void main( )
   {
      memcpy( s2, s1, 7 );
   }