view include/SDL_version.h @ 3162:dc1eb82ffdaa

Von: Thomas Zimmermann Betreff: [SDL] [PATCH] Make static variables const Datum: Tue, 19 May 2009 19:45:37 +0200 Hi, this is a set of simple changes which make some of SDL's internal static arrays constant. The purpose is to shrink the number of write-able static bytes and thus increase the number of memory pages shared between SDL applications. The patch set is against trunk@4513. Each of the attached patch files is specific to a sub-system. The set is completed by a second mail, because of the list's 40 KiB limit. The files readelf-r4513.txt and readelf-const-patch.txt where made by calling 'readelf -S libSDL.so'. They show the difference in ELF sections without and with the patch. Some numbers measured on my x86-64: Before [13] .rodata PROGBITS 00000000000eaaa0 000eaaa0 0000000000008170 0000000000000000 A 0 0 32 [19] .data.rel.ro PROGBITS 00000000003045e0 001045e0 00000000000023d0 0000000000000000 WA 0 0 32 [23] .data PROGBITS 00000000003076e0 001076e0 0000000000004988 0000000000000000 WA 0 0 32 After [13] .rodata PROGBITS 00000000000eaaa0 000eaaa0 0000000000009a50 0000000000000000 A 0 0 32 [19] .data.rel.ro PROGBITS 0000000000306040 00106040 0000000000002608 0000000000000000 WA 0 0 32 [23] .data PROGBITS 0000000000309360 00109360 0000000000002e88 0000000000000000 WA 0 0 32 The size of the write-able data section decreased considerably. Some entries became const-after-relocation, while most of its content went straight into the read-only data section. Best regards, Thomas
author Sam Lantinga <slouken@libsdl.org>
date Wed, 03 Jun 2009 04:37:27 +0000
parents 972a69e47cd9
children d3baf5ac4e37
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/

/**
 * \file SDL_version.h
 *
 * This header defines the current SDL version
 */

#ifndef _SDL_version_h
#define _SDL_version_h

#include "SDL_stdinc.h"
#include "SDL_revision.h"

#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
extern "C" {
/* *INDENT-ON* */
#endif

/**
 * \struct SDL_version
 * \brief Information the version of SDL in use.
 *
 * Represents the library's version as three levels: major revision
 *  (increments with massive changes, additions, and enhancements),
 *  minor revision (increments with backwards-compatible changes to the
 *  major revision), and patchlevel (increments with fixes to the minor
 *  revision).
 *
 * \sa SDL_VERSION
 * \sa SDL_GetVersion
 */
typedef struct SDL_version
{
    Uint8 major;        /**< major version */
    Uint8 minor;        /**< minor version */
    Uint8 patch;        /**< update version */
} SDL_version;

/* Printable format: "%d.%d.%d", MAJOR, MINOR, PATCHLEVEL
*/
#define SDL_MAJOR_VERSION	1
#define SDL_MINOR_VERSION	3
#define SDL_PATCHLEVEL		0

/**
 * \def SDL_VERSION(x)
 * \brief Macro to determine SDL version program was compiled against.
 *
 * This macro fills in a SDL_version structure with the version of the
 *  library you compiled against. This is determined by what header the
 *  compiler uses. Note that if you dynamically linked the library, you might
 *  have a slightly newer or older version at runtime. That version can be
 *  determined with SDL_GetVersion(), which, unlike SDL_VERSION,
 *  is not a macro.
 *
 * \param x A pointer to a SDL_version struct to initialize.
 *
 * \sa SDL_version
 * \sa SDL_GetVersion
 */
#define SDL_VERSION(x)							\
{									\
	(x)->major = SDL_MAJOR_VERSION;					\
	(x)->minor = SDL_MINOR_VERSION;					\
	(x)->patch = SDL_PATCHLEVEL;					\
}

/* This macro turns the version numbers into a numeric value:
   (1,2,3) -> (1203)
   This assumes that there will never be more than 100 patchlevels
*/
#define SDL_VERSIONNUM(X, Y, Z)						\
	((X)*1000 + (Y)*100 + (Z))

/* This is the version number macro for the current SDL version */
#define SDL_COMPILEDVERSION \
	SDL_VERSIONNUM(SDL_MAJOR_VERSION, SDL_MINOR_VERSION, SDL_PATCHLEVEL)

/* This macro will evaluate to true if compiled with SDL at least X.Y.Z */
#define SDL_VERSION_ATLEAST(X, Y, Z) \
	(SDL_COMPILEDVERSION >= SDL_VERSIONNUM(X, Y, Z))

/**
 * \fn void SDL_GetVersion(SDL_version *ver)
 * \brief Get the version of SDL that is linked against your program.
 *
 * If you are using a shared library (DLL) version of SDL, then it is
 *  possible that it will be different than the version you compiled against.
 *
 * This is a real function; the macro SDL_VERSION tells you what version
 *  of SDL you compiled against:
 *
 * \code
 * SDL_version compiled;
 * SDL_version linked;
 *
 * SDL_VERSION(&compiled);
 * SDL_GetVersion(&linked);
 * printf("We compiled against SDL version %d.%d.%d ...\n",
 *           compiled.major, compiled.minor, compiled.patch);
 * printf("But we linked against SDL version %d.%d.%d.\n",
 *           linked.major, linked.minor, linked.patch);
 * \endcode
 *
 * This function may be called safely at any time, even before SDL_Init().
 *
 * \sa SDL_VERSION
 */
extern DECLSPEC void SDLCALL SDL_GetVersion(SDL_version * ver);

/**
 * \fn int SDL_GetRevision(void)
 * \brief Get the code revision of SDL that is linked against your program.
 */
extern DECLSPEC int SDLCALL SDL_GetRevision(void);

/* Ends C function definitions when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
}
/* *INDENT-ON* */
#endif
#include "close_code.h"

#endif /* _SDL_version_h */

/* vi: set ts=4 sw=4 expandtab: */