Function Modifiers

This section presents descriptions of the function modifiers available with the CodeGear C++ compiler.

You can use the __declspec(dllexport), and __declspec(dllimport)and __saveregs modifiers to modify functions.

In 32-bit programs the keyword can be applied to class, function, and variable declarations

The __declspec(dllexport) modifier makes the function exportable from Windows. The __declspec(dllimport) modifier makes a function available to a Windows program. The keywords are used in an executable (if you don't use smart callbacks) or in a DLL.

Functions declared with the __fastcall modifier have different names than their non-__fastcall counterparts. The compiler prefixes the __fastcall function name with an @. This prefix applies to both unmangled C function names and to mangled C++ function names.

CodeGear C++ modifiers

Modifier	Use with	Description
const1	Variables	Prevents changes to object.
volatile1	Variables	Prevents register allocation and some optimization. Warns compiler that object might be subject to outside change during evaluation.
__cdecl2	Functions	Forces C argument-passing convention. Affects linker and link-time names.
__cdecl2	Variables	Forces global identifier case-sensitivity and leading underscores in C.
__pascal	Functions	Forces Pascal argument-passing convention. Affects linker and link-time names.
__pascal	Variables	Forces global identifier case-insensitivity with no leading underscores in C.
__import	Functions/classes	Tells the compiler which functions or classes to import.
__export	Functions/classes	Tells the compiler which functions or classes to export.
__declspec(dllimport)	Functions/classes	Tells the compiler which functions or classes to import. This is the preferred method.
__declspec(dllexport)	Functions/classes	Tells the compiler which functions or classes to export. This is the preferred method.
__fastcall	Functions	Forces register parameter passing convention. Affects the linker and link-time names.
__stdcall	Function	Forces the standard WIN32 argument-passing convention.

C++ extends const and volatile to include classes and member functions.
This is the default.