INFO: Must Use Prototype Before Intrinsic or Function Pragmas

ID: Q41212

The information in this article applies to:

The 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, 16-bit edition, versions 1.0, 1.5, 1.51, 1.52
- Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 4.0, 5.0, 6.0

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 )

where a_CFunction is a C Run-time library routine, the compiler generates the following error:

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

if the /Oi option is not used. The same is true for the following statement to force use of the intrinsic:


   #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 );
}

Additional query words: 8.00 8.00c 9.00 9.10

Keywords : kbcode kbCompiler kbVC100 kbVC150 kbVC151 kbVC152 kbVC200 kbVC210 kbVC400 kbVC500 kbVC600
Version : MS-DOS:6.0,6.00a,6.00ax,7.0; WINDOWS:1.0,1.5,1.51,1.52; WINDOWS NT:1.0,2.0,2.1,4.0,5.0
Platform : MS-DOS NT WINDOWS
Issue type : kbinfo