Using the GNU Compiler Collection Richard M. Stallman Last updated 30 December 2002 for GCC 3.3 For GCC Version 3.3 Published by the Free Software Foundation 59 Temple Place—Suite 330 Boston, MA 02111­1307, USA Last printed April, 1998. Printed copies are available for $50 each. Copyright c 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003 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 Front­Cover texts being (a) (see below), and with the Back­Cover Texts being (b) (see below). A copy of the license is included in the section entitled “GNU Free Documentation License”. (a) The FSF's Front­Cover Text is: A GNU Manual (b) The FSF's Back­Cover 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 develop­ ment. i Short Contents Introduction . 1 1 Compile C, C++, Objective­C, Ada, Fortran, Java, or treelang. 3 2 Language Standards Supported by GCC. 5 3 GCC Command Options . 9 4 C Implementationdefined behavior . 165 5 Extensions to the C Language Family . 171 6 Extensions to the C++ Language . 273 7 GNU Objective­C runtime features . 283 8 Binary Compatibility. 289 9 gcov—a Test Coverage Program . 293 10 Known Causes of Trouble with GCC . 301 11 Reporting Bugs . 319 12 How To Get Help with GCC . 325 13 Contributing to GCC Development . 327 14 Using GCC on VMS . 329 Funding Free Software . 333 The GNU Project and GNU/Linux. 335 GNU GENERAL PUBLIC LICENSE . 337 GNU Free Documentation License . 343 Contributors to GCC . 351 Option Index . 361 Keyword Index . 373 ii Using the GNU Compiler Collection (GCC) iii Table of Contents Introduction . 1 1 Compile C, C++, Objective­C, Ada, Fortran, Java, or treelang . 3 2 Language Standards Supported by GCC . 5 3 GCC Command Options . 9 3.1 Option Summary . 9 3.2 Options Controlling the Kind of Output . 19 3.3 Compiling C++ Programs . 22 3.4 Options Controlling C Dialect . 22 3.5 Options Controlling C++ Dialect . 26 3.6 Options Controlling Objective­C Dialect. 33 3.7 Options to Control Diagnostic Messages Formatting . 34 3.8 Options to Request or Suppress Warnings . 35 3.9 Options for Debugging Your Program or GCC . 47 3.10 Options That Control Optimization . 55 3.11 Options Controlling the Preprocessor . 71 3.12 Passing Options to the Assembler . 79 3.13 Options for Linking . 79 3.14 Options for Directory Search. 82 3.15 Specifying subprocesses and the switches to pass to them . 83 3.16 Specifying Target Machine and Compiler Version . 90 3.17 Hardware Models and Configurations . 90 3.17.1 M680x0 Options . 90 3.17.2 M68hc1x Options . 93 3.17.3 VAX Options . 93 3.17.4 SPARC Options . 93 3.17.5 ARM Options. 97 3.17.6 MN10200 Options . 101 3.17.7 MN10300 Options . 101 3.17.8 M32R/D Options. 102 3.17.9 M88K Options . 103 3.17.10 IBM RS/6000 and PowerPC Options . 106 3.17.11 Darwin Options . 114 3.17.12 IBM RT Options . 114 3.17.13 MIPS Options . 115 3.17.14 Intel 386 and AMD x86­64 Options . 120 3.17.15 HPPA Options . 125 iv Using the GNU Compiler Collection (GCC) 3.17.16 Intel 960 Options . 128 3.17.17 DEC Alpha Options . 129 3.17.18 DEC Alpha/VMS Options . 133 3.17.19 H8/300 Options . 133 3.17.20 SH Options . 134 3.17.21 Options for System V . 135 3.17.22 TMS320C3x/C4x Options. 135 3.17.23 V850 Options. 137 3.17.24 ARC Options . 138 3.17.25 NS32K Options. 139 3.17.26 AVR Options . 141 3.17.27 MCore Options. 141 3.17.28 IA­64 Options . 142 3.17.29 D30V Options . 143 3.17.30 S/390 and zSeries Options . 144 3.17.31 CRIS Options. 145 3.17.32 MMIX Options . 146 3.17.33 PDP­11 Options . 147 3.17.34 Xstormy16 Options . 148 3.17.35 FRV Options . 149 3.17.36 Xtensa Options . 151 3.18 Options for Code Generation Conventions . 153 3.19 Environment Variables Affecting GCC . 159 3.20 Running Protoize . 162 4 C Implementationdefined behavior . 165 4.1 Translation . 165 4.2 Environment . 165 4.3 Identifiers . 165 4.4 Characters. 165 4.5 Integers . ..