RealView Compilation Tools Compiler Reference Guide - ARM ...

Compiler-specific Features
• __attribute__((noinline)) on page 4-32.
4.6.13 #pragma no_pch
This pragma suppresses PCH processing for a given source file.
See also
• --pch on page 2-70
• Precompiled header files on page 2-16 in the Compiler User Guide.
4.6.14 #pragma Onum
This pragma changes the optimization level.
Syntax
#pragma Onum
Where:
num
is the new optimization level.
The value of num is 0, 1, 2 or 3.
See also
• -Onum on page 2-66.
4.6.15 #pragma once
This pragma enables the compiler to skips subsequent includes of that header file.
#pragma once is accepted for compatibility with other compilers, and enables you to use
other forms of header guard coding. However, it is preferable to use #ifndef and #define
coding because this is more portable.
Example
The following example shows the placement of a #ifndef guard around the body of the
file, with a #define of the guard variable after the #ifndef.
#ifndef FILE_H
#define FILE_H
#pragma once
// optional
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