AN3350 datasheet(163/185 Pages) STMICROELECTRONICS

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AN3350

Pragmas for preprocessing

Doc ID 018512 Rev 2

163/185

20.19

srcrelincludes

Controls the lookup of #include files.

Syntax

#pragma srcrelincludes on | off | reset

Remarks

When on, the compiler looks for #include files relative to the previously included file (not

just the source file). When off, the compiler uses the access paths specified with the -ir

option.

Use this pragma when multiple files use the same file name and are intended to be included

by another header file in that directory. This is a common practice in UNIX programming.

By default, this pragma is off.

20.20

syspath_once

Controls how included files are treated when #pragma once is enabled.

Syntax

#pragma syspath_once on | off | reset

Remarks

When this pragma and pragma once are set to on, the compiler distinguishes between

identically-named header files referred to in

#include <file-name>

and

#include "file-name".

When this pragma is off and pragma once is on, the compiler will ignore a file that uses a

#include <file-name>

directive if it has previously encountered another directive of the form

#include "file-name"

for an identically-named header file.

Example 114 shows an example.

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

Example 114 Pragma syspath_once example

#pragma syspath_once off

#pragma once on /* Include all subsequent files only once. */

#include "sock.h"

#include <sock.h> /* Skipped because syspath_once is off. */

AN3350 Datasheet(PDF) 163 Page - STMicroelectronics