The first step in calling a DLL is to create a prototype record. Each DLL that you want to call requires a prototype record in the SYSPROCS table, a global system table.
The first line of the prototype record will contain the name of the module, which is typically the name of the DLL. For example, the DLL_USER32 prototype references the module USER32.DLL. The recommended convention for naming prototype records is DLL_, suffixed by the name of the module.
Each function is defined on a separate line, starting in the second line of the prototype record. The function definition has four parts:
- Return Value Type
- Calling Convention
- Exported Function Name
- Parameter Type
- Optional Function Name Alias
Each element is described in the sections that follow.