一本介绍linux基础知识的书籍

												Using the GNU Compiler Collection (GCC)																				Copyright © 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,				1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.								   Permission is granted to copy, distribute and/or modify this document				under the terms of the GNU Free Documentation License, Version 1.2 or				any later version published by the Free Software Foundation; with the				Invariant Sections being "GNU General Public License" and "Funding				Free Software", the Front-Cover texts being (a) (see below), and with				the Back-Cover Texts being (b) (see below).  A copy of the license is				included in the section entitled "GNU Free Documentation License".								   (a) The FSF's Front-Cover Text is:								   A GNU Manual								   (b) The FSF's Back-Cover Text is:								   You have freedom to copy and modify this GNU Manual, like GNU				     software.  Copies published by the Free Software Foundation raise				     funds for GNU development.-->												  pre.display { font-family:inherit }				  pre.format  { font-family:inherit }				  pre.smalldisplay { font-family:inherit; font-size:smaller }				  pre.smallformat  { font-family:inherit; font-size:smaller }				  pre.smallexample { font-size:smaller }				  pre.smalllisp    { font-size:smaller }				-->																				Node: Alternate Keywords,				Next: Incomplete Enums,				Previous: Explicit Reg Vars,				Up: C Extensions																Alternate Keywords								-ansi and the various -std options disable certain				keywords.  This causes trouble when you want to use GNU C extensions, or				a general-purpose header file that should be usable by all programs,				including ISO C programs.  The keywords asm, typeof and				inline are not available in programs compiled with				-ansi or -std (although inline can be used in a				program compiled with -std=c99).  The ISO C99 keyword				restrict is only available when -std=gnu99 (which will				eventually be the default) or -std=c99 (or the equivalent				-std=iso9899:1999) is used.								   The way to solve these problems is to put __ at the beginning and				end of each problematical keyword.  For example, use __asm__				instead of asm, and __inline__ instead of inline.								   Other C compilers won't accept these alternative keywords; if you want to				compile with another compiler, you can define the alternate keywords as				macros to replace them with the customary keywords.  It looks like this:								     #ifndef __GNUC__				     #define __asm__ asm				     #endif				     								   -pedantic and other options cause warnings for many GNU C extensions. 				You can				prevent such warnings within one expression by writing				__extension__ before the expression.  __extension__ has no				effect aside from this.