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Compiler User Guide

Conventions and Feedback Overview of the Compiler Getting Started with the Compiler Compiler Features Compiler intrinsics Performance benefits of compiler intrinsics ARM assembler instruction intrinsics supported by Generic intrinsics supported by the compiler Compiler intrinsics for controlling IRQ and FIQ in Compiler intrinsics for inserting optimization bar Compiler intrinsics for inserting native instructi Compiler intrinsics for Digital Signal Processing European Telecommunications Standards Institute (E Compiler support for European Telecommunications S Overflow and carry status flags for C and C++ code Texas Instruments (TI) C55x intrinsics for optimiz Compiler support for accessing registers using nam Pragmas recognized by the compiler Compiler and processor support for bit-banding Compiler type attribute, __attribute__((bitband)) --bitband compiler command-line option How the compiler handles bit-band objects placed o Compiler support for thread-local storage Compiler eight-byte alignment features Using compiler and linker support for symbol versi PreCompiled Header (PCH) files Automatic PreCompiled Header (PCH) file processing PreCompiled Header (PCH) file processing and the h PreCompiled Header (PCH) file creation requirement Compilation with multiple PreCompiled Header (PCH) Obsolete PreCompiled Header (PCH) files Manually specifying the filename and location of a Selectively applying PreCompiled Header (PCH) file Suppressing PreCompiled Header (PCH) file processi Message output during PreCompiled Header (PCH) pro Performance issues with PreCompiled Header (PCH) f Default compiler options that are affected by opti Compiler Coding Practices Compiler Diagnostic Messages Using the Inline and Embedded Assemblers of the AR

PreCompiled Header (PCH) file processing and the header stop point

PreCompiled Header (PCH) file processing and the header stop point

The PCH file contains a snapshot of all the code that precedes a header stop point. Typically, the header stop point is the first token in the primary source file that does not belong to a preprocessing directive. In the following example, the header stop point is int and the PCH file contains a snapshot that reflects the inclusion of xxx.h and yyy.h:

#include "xxx.h"
#include "yyy.h"
int i;

The header stop point can be manually specified with #pragma hdrstop. If used, this pragma must be placed before the first token that does not belong to a preprocessing directive. In this example, it must be placed before int, as follows:

#include "xxx.h"
#include "yyy.h"

#pragma hdrstop
int i;

If a #if block encloses the first non-preprocessor token or #pragma hdrstop, the header stop point is the outermost enclosing #if. For example:

#include "xxx.h"
#ifndef YYY_H
#define YYY_H 1
#include "yyy.h"
#endif
#if TEST /* Header stop point lies immediately before #if TEST */
int i;
#endif

In this example, the first token that does not belong to a preprocessing directive is int, but the header stop point is the start of the #if block containing it. The PCH file reflects the inclusion of xxx.h and, conditionally, the definition of YYY_H and inclusion of yyy.h. It does not contain the state produced by #if TEST.

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