AN3350 datasheet(130/185 Pages) STMICROELECTRONICS

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Pragmas for standard C conformance

AN3350

130/185

Doc ID 018512 Rev 2

Remarks

If you enable this pragma, the compiler ignores old-style function declarations and lets you

prototype a function any way you want. In old-style declarations, you specify the types of

arguments on separate lines instead of the function’s argument list. For example, the code

in Example 79 defines a prototype for a function with an old-style definition.

Example 79 Mixing old-style and prototype function declarations

int f(char x, short y, float z);

#pragma ignore_oldstyle on

f(x, y, z)

char x;

short y;

float z;

{

return (int)x+y+z;

}

#pragma ignore_oldstyle reset

This pragma does not correspond to any panel setting. By default, this setting is disabled.

17.5

only_std_keywords

Controls the use of ISO/IEC keywords.

Syntax

#pragma only_std_keywords on | off | reset

Remarks

The compiler recognizes additional reserved keywords. If you are writing source code that

must follow the ISO/IEC C standards strictly, enable the pragma only_std_keywords.

By default, this pragma is disabled.

17.6

require_prototypes

Controls whether or not the compiler should expect function prototypes.

Syntax

#pragma require_prototypes on | off | reset

Remarks

This pragma only affects non-static functions.

If you enable this pragma, the compiler generates an error message if you use a function

that does not have a preceding prototype. Use this pragma to prevent error messages

AN3350 Datasheet(PDF) 130 Page - STMicroelectronics