#pragma expected_value

Purpose

Specifies the value that a parameter passed in a function call is most likely to take at run time. The compiler can use this information to perform certain optimizations, such as function cloning and inlining.

Syntax


>>-#pragma expected_value--(--argument--,--value--)------------><

Parameters

argument: The name of the parameter for which you want to provide the expected value. The parameter must be of a simple built-in integral, Boolean, character, or floating-point type.
value: A constant literal representing the value that you expect will most likely be taken by the parameter at run time. value can be an expression as long as it is a compile time constant expression.

Usage

The directive must appear inside the body of a function definition, before the first statement (including declaration statements). It is not supported within nested functions.

If you specify an expected value of a type different from that of the declared type of the parameter variable, the value will be implicitly converted only if allowed. Otherwise, a warning is issued.

For each parameter that will be provided the expected value there is a limit of one directive. Parameters that will not be provided the expected value do not require a directive.

Examples

The following example tells the compiler that the most likely values for parameters a and b are 1 and 0, respectively:

int func(int a,int b)
{
#pragma expected_value(a,1)
#pragma expected_value(b,0)
...
...
}

Related information

#pragma execution_frequency