The __cdecl convention is the convention used by the compiler. The following list shows the implementation of this calling convention:
| Element | Implementation |
| Argument-passing order | Right to left |
| Argument-passing convention | By value, unless a pointer or reference type is passed |
| Stack-maintenance responsibility | Calling function adjusts the stack |
| Name-decoration convention | Underscore character (_) is prefixed to names |
| Case-translation convention | No case translation performed |
To declare a function as __cdecl, use a declaration of the form:
char * __cdecl stricmp( char *szString1,
char *szString2 );
Note that, in the preceding declaration, the modifier __cdecl modifies the name immediately to its right, stricmp.
The following list shows how values are returned from functions specified as __cdecl:
| Type | Return Location |
| char, unsigned char | Returned in AL register. |
| int, unsigned, short, unsigned short, “pointer to near” | Returned in AX register. |
| long, unsigned long | Returned in DX:AX registers. |
| float, double | Copied to the global variable __fac; returns a pointer to __fac in AX or DX:AX, depending on addressing model. |
| long double | Placed on the NDP (numeric data processor) stack using the FLD instruction. |
| Structures | Depends on the size of the structure: |
| 1 byte: returned in AL register 2 bytes: returned in AX register 4 bytes: returned in DX:AX registers | |
| For structures larger than 4 bytes, the caller passes a pointer to a hidden variable that will receive the return value as the last item pushed. The structure being returned is copied into the location pointed to by the hidden variable. The pointer to the hidden variable is then returned in AX or DX:AX (for near or far addressing models, respectively). |
In 16-bit compilations, the variable-argument facility of ANSI C can be used only with functions of type __cdecl. In 32-bit compilations, variable-argument lists can also be used with the __stdcall calling convention, discussed on topic .