The CC-RH allows inline expansion of each function. This section explains how to specify inline expansion.

Inline expansion is used to expand the main body of a function at a location where the function is called. This decreases the overhead of function call and increases the possibility of optimization. As a result, the execution speed can be increased.

If inline expansion is executed, however, the object size increases.

Specify the function to be expanded inline using the #pragma inline directive.

#pragma inline ( function-name [, function-name]... )Note

Describe functions that are described in the C language. In the case of a function, "void func1() {}", specify "func1". Two or more function names can be specified with each delimited by "," (comma).

#pragma inline  func1, func2

void    func1() {...}

void    func2() {...}

void func(void) {

        func1();    /*function subject to inline expansion*/

        func2();    /*function subject to inline expansion*/

}

At least the following conditions must be satisfied for inline expansion of a function specified using the #pragma inline directive.

Inline expansion may not be executed even if the following conditions are satisfied, because of the internal processing of the CC-RH.

A function that expands inline and a function that is expanded inline, i.e., a function call and a function definition must be in the same file. This means that a function described in another C source cannot be expanded inline. If it is specified that a function described in another C source is expanded inline, the CC-RH does not output a warning message and ignores the specification.

If the #pragma inline directive is described after function definition, the CC-RH outputs a warning message and ignores the specification. However, prototype declaration of the function may be described in any order. Here is an example.

[Valid Inline Expansion Specification]

#pragma inline  func1, func2

void    func1();        /*prototype declaration*/

void    func2();        /*prototype declaration*/

void    func1() {...}   /*function definition*/

void    func2() {...}   /*function definition*/

[Invalid Inline Expansion Specification]

void    func1();        /*prototype declaration*/

void    func2();        /*prototype declaration*/

void    func1() {...}   /*function definition*/

void    func1() {...}   /*function definition*/

#pragma inline  func1, func2

If the number of arguments is different between "call" and "definition" of the function to be expanded inline, the CC-RH ignores the specification.

If the number of arguments is different between "call" and "definition" of the function to be expanded inline, the CC-RH ignores the specification. If the type of the argument is the integer type (including enum) or pointer-type, and in the same size, however, inline expansion is executed.

If inline expansion is specified for a function with a variable arguments, the CC-RH outputs neither an error nor warning message and ignores the specification.

If a recursive function that calls itself is specified for inline expansion, the CC-RH outputs neither an error nor warning message and ignores the specification. If two or more function calls are nested and if a code that calls itself exists, however, inline expansion may be executed.

If you call a function for inline expansion via its address, then the inline expansion specification will be ignored, without outputting an error or warning message.

When using the -Oinline option, use #pragma noinline to prevent inline expansion of a specific function.

#pragma noinline ( function-name [, function-name]... )Note

#pragma inline_asm, #pragma inline, #pragma noinline, #pragma interrupt,

#pragma block_interrupt, #pragma stack_protector,

#pragma inline_asm, #pragma inline, #pragma noinline, #pragma interrupt,

#pragma block_interrupt

Here are differences in inline expansion operation depending on whether the #pragma inline directive or an option is specified.

Below is an example of inline expansion.

#pragma inline  (func)

static int      func(int a, int b)

{

        return  (a+b)/2;

}

int     x;

main()

{

        x = func (10, 20);

}

int     x;

main()

{

        int     func_result;

{

        int     a_1 = 10, b_1 = 20;

        func_result = (a_1+b_1)/2;

}

        x = func_result;

}