Using the GNU Compiler Collection For gcc version 5.4.0 (GCC) Richard M. Stallman and the GCC Developer Community Published by: GNU Press Website: http://www.gnupress.org a division of the General: [email protected] Free Software Foundation Orders: [email protected] 51 Franklin Street, Fifth Floor Tel 617-542-5942 Boston, MA 02110-1301 USA Fax 617-542-2652 Last printed October 2003 for GCC 3.3.1. Printed copies are available for $45 each. Copyright c 1988-2015 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 1.3 or any later version published by the Free Software Foundation; with the Invariant Sections being \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. i Short Contents Introduction ::::::::::::::::::::::::::::::::::::::::::::: 1 1 Programming Languages Supported by GCC ::::::::::::::: 3 2 Language Standards Supported by GCC :::::::::::::::::: 5 3 GCC Command Options ::::::::::::::::::::::::::::::: 9 4 C Implementation-Defined Behavior :::::::::::::::::::: 359 5 C++ Implementation-Defined Behavior ::::::::::::::::: 367 6 Extensions to the C Language Family ::::::::::::::::::: 369 7 Extensions to the C++ Language :::::::::::::::::::::: 647 8 GNU Objective-C Features ::::::::::::::::::::::::::: 661 9 Binary Compatibility :::::::::::::::::::::::::::::::: 677 10 gcov|a Test Coverage Program ::::::::::::::::::::::: 681 11 gcov-tool|an Offline Gcda Profile Processing Tool ::::::: 691 12 Known Causes of Trouble with GCC :::::::::::::::::::: 695 13 Reporting Bugs ::::::::::::::::::::::::::::::::::::: 711 14 How To Get Help with GCC :::::::::::::::::::::::::: 713 15 Contributing to GCC Development ::::::::::::::::::::: 715 Funding Free Software ::::::::::::::::::::::::::::::::::: 717 The GNU Project and GNU/Linux::::::::::::::::::::::::: 719 GNU General Public License :::::::::::::::::::::::::::::: 721 GNU Free Documentation License ::::::::::::::::::::::::: 733 Contributors to GCC :::::::::::::::::::::::::::::::::::: 741 Option Index :::::::::::::::::::::::::::::::::::::::::: 759 Keyword Index ::::::::::::::::::::::::::::::::::::::::: 781 iii Table of Contents Introduction :::::::::::::::::::::::::::::::::::::::: 1 1 Programming Languages Supported by GCC ::::::::::::::::::::::::::::::::::::::::::::::::: 3 2 Language Standards Supported by GCC ::::: 5 2.1 C Language :::::::::::::::::::::::::::::::::::::::::::::::::::: 5 2.2 C++ Language :::::::::::::::::::::::::::::::::::::::::::::::: 6 2.3 Objective-C and Objective-C++ Languages :::::::::::::::::::: 7 2.4 Go Language::::::::::::::::::::::::::::::::::::::::::::::::::: 8 2.5 References for Other Languages :::::::::::::::::::::::::::::::: 8 3 GCC Command Options ::::::::::::::::::::::: 9 3.1 Option Summary::::::::::::::::::::::::::::::::::::::::::::::: 9 3.2 Options Controlling the Kind of Output ::::::::::::::::::::::: 26 3.3 Compiling C++ Programs :::::::::::::::::::::::::::::::::::: 31 3.4 Options Controlling C Dialect ::::::::::::::::::::::::::::::::: 32 3.5 Options Controlling C++ Dialect ::::::::::::::::::::::::::::: 38 3.6 Options Controlling Objective-C and Objective-C++ Dialects :: 49 3.7 Options to Control Diagnostic Messages Formatting ::::::::::: 53 3.8 Options to Request or Suppress Warnings ::::::::::::::::::::: 55 3.9 Options for Debugging Your Program or GCC ::::::::::::::::: 83 3.10 Options That Control Optimization ::::::::::::::::::::::::: 110 3.11 Options Controlling the Preprocessor:::::::::::::::::::::::: 168 3.12 Passing Options to the Assembler ::::::::::::::::::::::::::: 179 3.13 Options for Linking ::::::::::::::::::::::::::::::::::::::::: 179 3.14 Options for Directory Search :::::::::::::::::::::::::::::::: 184 3.15 Specifying Subprocesses and the Switches to Pass to Them :: 186 3.16 Specifying Target Machine and Compiler Version :::::::::::: 193 3.17 Hardware Models and Configurations ::::::::::::::::::::::: 193 3.17.1 AArch64 Options :::::::::::::::::::::::::::::::::::::: 193 3.17.1.1 `-march' and `-mcpu' Feature Modifiers :::::::::::: 196 3.17.2 Adapteva Epiphany Options ::::::::::::::::::::::::::: 196 3.17.3 ARC Options :::::::::::::::::::::::::::::::::::::::::: 198 3.17.4 ARM Options:::::::::::::::::::::::::::::::::::::::::: 204 3.17.5 AVR Options :::::::::::::::::::::::::::::::::::::::::: 210 3.17.5.1 EIND and Devices with More Than 128 Ki Bytes of Flash::::::::::::::::::::::::::::::::::::::::::::::::::: 214 3.17.5.2 Handling of the RAMPD, RAMPX, RAMPY and RAMPZ Special Function Registers:::::::::::::::::::::::::::::::::::::: 216 3.17.5.3 AVR Built-in Macros:::::::::::::::::::::::::::::: 216 3.17.6 Blackfin Options ::::::::::::::::::::::::::::::::::::::: 218 iv Using the GNU Compiler Collection (GCC) 3.17.7 C6X Options::::::::::::::::::::::::::::::::::::::::::: 221 3.17.8 CRIS Options:::::::::::::::::::::::::::::::::::::::::: 222 3.17.9 CR16 Options ::::::::::::::::::::::::::::::::::::::::: 223 3.17.10 Darwin Options::::::::::::::::::::::::::::::::::::::: 224 3.17.11 DEC Alpha Options :::::::::::::::::::::::::::::::::: 227 3.17.12 FR30 Options :::::::::::::::::::::::::::::::::::::::: 232 3.17.13 FRV Options ::::::::::::::::::::::::::::::::::::::::: 232 3.17.14 GNU/Linux Options :::::::::::::::::::::::::::::::::: 236 3.17.15 H8/300 Options::::::::::::::::::::::::::::::::::::::: 236 3.17.16 HPPA Options:::::::::::::::::::::::::::::::::::::::: 237 3.17.17 IA-64 Options :::::::::::::::::::::::::::::::::::::::: 240 3.17.18 LM32 Options :::::::::::::::::::::::::::::::::::::::: 243 3.17.19 M32C Options :::::::::::::::::::::::::::::::::::::::: 244 3.17.20 M32R/D Options ::::::::::::::::::::::::::::::::::::: 244 3.17.21 M680x0 Options :::::::::::::::::::::::::::::::::::::: 245 3.17.22 MCore Options ::::::::::::::::::::::::::::::::::::::: 251 3.17.23 MeP Options ::::::::::::::::::::::::::::::::::::::::: 251 3.17.24 MicroBlaze Options ::::::::::::::::::::::::::::::::::: 253 3.17.25 MIPS Options :::::::::::::::::::::::::::::::::::::::: 255 3.17.26 MMIX Options ::::::::::::::::::::::::::::::::::::::: 268 3.17.27 MN10300 Options :::::::::::::::::::::::::::::::::::: 269 3.17.28 Moxie Options :::::::::::::::::::::::::::::::::::::::: 270 3.17.29 MSP430 Options:::::::::::::::::::::::::::::::::::::: 270 3.17.30 NDS32 Options ::::::::::::::::::::::::::::::::::::::: 271 3.17.31 Nios II Options ::::::::::::::::::::::::::::::::::::::: 273 3.17.32 Nvidia PTX Options :::::::::::::::::::::::::::::::::: 277 3.17.33 PDP-11 Options :::::::::::::::::::::::::::::::::::::: 277 3.17.34 picoChip Options ::::::::::::::::::::::::::::::::::::: 278 3.17.35 PowerPC Options::::::::::::::::::::::::::::::::::::: 279 3.17.36 RL78 Options::::::::::::::::::::::::::::::::::::::::: 279 3.17.37 IBM RS/6000 and PowerPC Options :::::::::::::::::: 279 3.17.38 RX Options :::::::::::::::::::::::::::::::::::::::::: 295 3.17.39 S/390 and zSeries Options :::::::::::::::::::::::::::: 298 3.17.40 Score Options::::::::::::::::::::::::::::::::::::::::: 301 3.17.41 SH Options ::::::::::::::::::::::::::::::::::::::::::: 301 3.17.42 Solaris 2 Options ::::::::::::::::::::::::::::::::::::: 309 3.17.43 SPARC Options :::::::::::::::::::::::::::::::::::::: 310 3.17.44 SPU Options ::::::::::::::::::::::::::::::::::::::::: 315 3.17.45 Options for System V ::::::::::::::::::::::::::::::::: 317 3.17.46 TILE-Gx Options ::::::::::::::::::::::::::::::::::::: 317 3.17.47 TILEPro Options ::::::::::::::::::::::::::::::::::::: 318 3.17.48 V850 Options ::::::::::::::::::::::::::::::::::::::::: 318 3.17.49 VAX Options ::::::::::::::::::::::::::::::::::::::::: 321 3.17.50 Visium Options ::::::::::::::::::::::::::::::::::::::: 321 3.17.51 VMS Options ::::::::::::::::::::::::::::::::::::::::: 322 3.17.52 VxWorks Options ::::::::::::::::::::::::::::::::::::: 322 3.17.53 x86 Options :::::::::::::::::::::::::::::::::::::::::: 323 3.17.54 x86 Windows Options::::::::::::::::::::::::::::::::: 339 v 3.17.55 Xstormy16 Options ::::::::::::::::::::::::::::::::::: 340 3.17.56 Xtensa Options ::::::::::::::::::::::::::::::::::::::: 340 3.17.57 zSeries Options ::::::::::::::::::::::::::::::::::::::: 342 3.18 Options for Code Generation Conventions ::::::::::::::::::: 342 3.19 Environment Variables Affecting GCC :::::::::::::::::::::: 353 3.20 Using Precompiled Headers ::::::::::::::::::::::::::::::::: 355 4 C Implementation-Defined Behavior ::::::: 359 4.1 Translation :::::::::::::::::::::::::::::::::::::::::::::::::: 359 4.2 Environment::::::::::::::::::::::::::::::::::::::::::::::::: 359 4.3 Identifiers:::::::::::::::::::::::::::::::::::::::::::::::::::: 359 4.4 Characters ::::::::::::::::::::::::::::::::::::::::::::::::::: 360 4.5 Integers:::::::::::::::::::::::::::::::::::::::::::::::::::::: 361 4.6 Floating Point ::::::::::::::::::::::::::::::::::::::::::::::: 361 4.7 Arrays and Pointers:::::::::::::::::::::::::::::::::::::::::: 362 4.8 Hints :::::::::::::::::::::::::::::::::::::::::::::::::::::::: 363 4.9 Structures, Unions, Enumerations, and Bit-Fields::::::::::::: 363 4.10 Qualifiers ::::::::::::::::::::::::::::::::::::::::::::::::::: 364 4.11 Declarators ::::::::::::::::::::::::::::::::::::::::::::::::: 365 4.12 Statements :::::::::::::::::::::::::::::::::::::::::::::::::