Top (Using the GNU Compiler Collection (GCC))

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1 Programming Languages Supported by GCC
2 Language Standards Supported by GCC
- 2.1 C Language
- 2.2 C++ Language
- 2.3 Objective-C and Objective-C++ Languages
- 2.4 Go Language
- 2.5 D language
- 2.6 References for Other Languages
3 GCC Command Options
- 3.1 Option Summary
- 3.2 Options Controlling the Kind of Output
- 3.3 Compiling C++ Programs
- 3.4 Options Controlling C Dialect
- 3.5 Options Controlling C++ Dialect
- 3.6 Options Controlling Objective-C and Objective-C++ Dialects
- 3.7 Options to Control Diagnostic Messages Formatting
- 3.8 Options to Request or Suppress Warnings
- 3.9 Options That Control Static Analysis
- 3.10 Options for Debugging Your Program
- 3.11 Options That Control Optimization
- 3.12 Program Instrumentation Options
- 3.13 Options Controlling the Preprocessor
- 3.14 Passing Options to the Assembler
- 3.15 Options for Linking
- 3.16 Options for Directory Search
- 3.17 Options for Code Generation Conventions
- 3.18 GCC Developer Options
- 3.19 Machine-Dependent Options
  - 3.19.1 AArch64 Options
    - 3.19.1.1 -march and -mcpu Feature Modifiers
  - 3.19.2 Adapteva Epiphany Options
  - 3.19.3 AMD GCN Options
  - 3.19.4 ARC Options
  - 3.19.5 ARM Options
  - 3.19.6 AVR Options
    - 3.19.6.1 EIND and Devices with More Than 128 Ki Bytes of Flash
    - 3.19.6.2 Handling of the RAMPD, RAMPX, RAMPY and RAMPZ Special Function Registers
    - 3.19.6.3 AVR Built-in Macros
  - 3.19.7 Blackfin Options
  - 3.19.8 C6X Options
  - 3.19.9 CRIS Options
  - 3.19.10 CR16 Options
  - 3.19.11 C-SKY Options
  - 3.19.12 Darwin Options
  - 3.19.13 DEC Alpha Options
  - 3.19.14 eBPF Options
  - 3.19.15 FR30 Options
  - 3.19.16 FT32 Options
  - 3.19.17 FRV Options
  - 3.19.18 GNU/Linux Options
  - 3.19.19 H8/300 Options
  - 3.19.20 HPPA Options
  - 3.19.21 IA-64 Options
  - 3.19.22 LM32 Options
  - 3.19.23 LoongArch Options
  - 3.19.24 M32C Options
  - 3.19.25 M32R/D Options
  - 3.19.26 M680x0 Options
  - 3.19.27 MCore Options
  - 3.19.28 MeP Options
  - 3.19.29 MicroBlaze Options
  - 3.19.30 MIPS Options
  - 3.19.31 MMIX Options
  - 3.19.32 MN10300 Options
  - 3.19.33 Moxie Options
  - 3.19.34 MSP430 Options
  - 3.19.35 NDS32 Options
  - 3.19.36 Nios II Options
  - 3.19.37 Nvidia PTX Options
  - 3.19.38 OpenRISC Options
  - 3.19.39 PDP-11 Options
  - 3.19.40 picoChip Options
  - 3.19.41 PowerPC Options
  - 3.19.42 PRU Options
  - 3.19.43 RISC-V Options
  - 3.19.44 RL78 Options
  - 3.19.45 IBM RS/6000 and PowerPC Options
  - 3.19.46 RX Options
  - 3.19.47 S/390 and zSeries Options
  - 3.19.48 Score Options
  - 3.19.49 SH Options
  - 3.19.50 Solaris 2 Options
  - 3.19.51 SPARC Options
  - 3.19.52 Options for System V
  - 3.19.53 TILE-Gx Options
  - 3.19.54 TILEPro Options
  - 3.19.55 V850 Options
  - 3.19.56 VAX Options
  - 3.19.57 Visium Options
  - 3.19.58 VMS Options
  - 3.19.59 VxWorks Options
  - 3.19.60 x86 Options
  - 3.19.61 x86 Windows Options
  - 3.19.62 Xstormy16 Options
  - 3.19.63 Xtensa Options
  - 3.19.64 zSeries Options
- 3.20 Specifying Subprocesses and the Switches to Pass to Them
- 3.21 Environment Variables Affecting GCC
- 3.22 Using Precompiled Headers
- 3.23 C++ Modules
  - 3.23.1 Module Mapper
  - 3.23.2 Module Preprocessing
  - 3.23.3 Compiled Module Interface
4 C Implementation-Defined Behavior
- 4.1 Translation
- 4.2 Environment
- 4.3 Identifiers
- 4.4 Characters
- 4.5 Integers
- 4.6 Floating Point
- 4.7 Arrays and Pointers
- 4.8 Hints
- 4.9 Structures, Unions, Enumerations, and Bit-Fields
- 4.10 Qualifiers
- 4.11 Declarators
- 4.12 Statements
- 4.13 Preprocessing Directives
- 4.14 Library Functions
- 4.15 Architecture
- 4.16 Locale-Specific Behavior
5 C++ Implementation-Defined Behavior
- 5.1 Conditionally-Supported Behavior
- 5.2 Exception Handling
6 Extensions to the C Language Family
- 6.1 Statements and Declarations in Expressions
- 6.2 Locally Declared Labels
- 6.3 Labels as Values
- 6.4 Nested Functions
- 6.5 Nonlocal Gotos
- 6.6 Constructing Function Calls
- 6.7 Referring to a Type with typeof
- 6.8 Conditionals with Omitted Operands
- 6.9 128-bit Integers
- 6.10 Double-Word Integers
- 6.11 Complex Numbers
- 6.12 Additional Floating Types
- 6.13 Half-Precision Floating Point
- 6.14 Decimal Floating Types
- 6.15 Hex Floats
- 6.16 Fixed-Point Types
- 6.17 Named Address Spaces
  - 6.17.1 AVR Named Address Spaces
  - 6.17.2 M32C Named Address Spaces
  - 6.17.3 PRU Named Address Spaces
  - 6.17.4 RL78 Named Address Spaces
  - 6.17.5 x86 Named Address Spaces
- 6.18 Arrays of Length Zero
- 6.19 Structures with No Members
- 6.20 Arrays of Variable Length
- 6.21 Macros with a Variable Number of Arguments.
- 6.22 Slightly Looser Rules for Escaped Newlines
- 6.23 Non-Lvalue Arrays May Have Subscripts
- 6.24 Arithmetic on void- and Function-Pointers
- 6.25 Pointer Arguments in Variadic Functions
- 6.26 Pointers to Arrays with Qualifiers Work as Expected
- 6.27 Non-Constant Initializers
- 6.28 Compound Literals
- 6.29 Designated Initializers
- 6.30 Case Ranges
- 6.31 Cast to a Union Type
- 6.32 Mixed Declarations, Labels and Code
- 6.33 Declaring Attributes of Functions
  - 6.33.1 Common Function Attributes
  - 6.33.2 AArch64 Function Attributes
    - 6.33.2.1 Inlining rules
  - 6.33.3 AMD GCN Function Attributes
  - 6.33.4 ARC Function Attributes
  - 6.33.5 ARM Function Attributes
  - 6.33.6 AVR Function Attributes
  - 6.33.7 Blackfin Function Attributes
  - 6.33.8 BPF Function Attributes
  - 6.33.9 CR16 Function Attributes
  - 6.33.10 C-SKY Function Attributes
  - 6.33.11 Epiphany Function Attributes
  - 6.33.12 H8/300 Function Attributes
  - 6.33.13 IA-64 Function Attributes
  - 6.33.14 M32C Function Attributes
  - 6.33.15 M32R/D Function Attributes
  - 6.33.16 m68k Function Attributes
  - 6.33.17 MCORE Function Attributes
  - 6.33.18 MeP Function Attributes
  - 6.33.19 MicroBlaze Function Attributes
  - 6.33.20 Microsoft Windows Function Attributes
  - 6.33.21 MIPS Function Attributes
  - 6.33.22 MSP430 Function Attributes
  - 6.33.23 NDS32 Function Attributes
  - 6.33.24 Nios II Function Attributes
  - 6.33.25 Nvidia PTX Function Attributes
  - 6.33.26 PowerPC Function Attributes
  - 6.33.27 RISC-V Function Attributes
  - 6.33.28 RL78 Function Attributes
  - 6.33.29 RX Function Attributes
  - 6.33.30 S/390 Function Attributes
  - 6.33.31 SH Function Attributes
  - 6.33.32 Symbian OS Function Attributes
  - 6.33.33 V850 Function Attributes
  - 6.33.34 Visium Function Attributes
  - 6.33.35 x86 Function Attributes
  - 6.33.36 Xstormy16 Function Attributes
- 6.34 Specifying Attributes of Variables
  - 6.34.1 Common Variable Attributes
  - 6.34.2 ARC Variable Attributes
  - 6.34.3 AVR Variable Attributes
  - 6.34.4 Blackfin Variable Attributes
  - 6.34.5 H8/300 Variable Attributes
  - 6.34.6 IA-64 Variable Attributes
  - 6.34.7 M32R/D Variable Attributes
  - 6.34.8 MeP Variable Attributes
  - 6.34.9 Microsoft Windows Variable Attributes
  - 6.34.10 MSP430 Variable Attributes
  - 6.34.11 Nvidia PTX Variable Attributes
  - 6.34.12 PowerPC Variable Attributes
  - 6.34.13 RL78 Variable Attributes
  - 6.34.14 V850 Variable Attributes
  - 6.34.15 x86 Variable Attributes
  - 6.34.16 Xstormy16 Variable Attributes
- 6.35 Specifying Attributes of Types
  - 6.35.1 Common Type Attributes
  - 6.35.2 ARC Type Attributes
  - 6.35.3 ARM Type Attributes
  - 6.35.4 BPF Type Attributes
  - 6.35.5 MeP Type Attributes
  - 6.35.6 PowerPC Type Attributes
  - 6.35.7 x86 Type Attributes
- 6.36 Label Attributes
- 6.37 Enumerator Attributes
- 6.38 Statement Attributes
- 6.39 Attribute Syntax
- 6.40 Prototypes and Old-Style Function Definitions
- 6.41 C++ Style Comments
- 6.42 Dollar Signs in Identifier Names
- 6.43 The Character ESC in Constants
- 6.44 Determining the Alignment of Functions, Types or Variables
- 6.45 An Inline Function is As Fast As a Macro
- 6.46 When is a Volatile Object Accessed?
- 6.47 How to Use Inline Assembly Language in C Code
  - 6.47.1 Basic Asm — Assembler Instructions Without Operands
  - 6.47.2 Extended Asm - Assembler Instructions with C Expression Operands
  - 6.47.3 Constraints for asm Operands
  - 6.47.4 Controlling Names Used in Assembler Code
  - 6.47.5 Variables in Specified Registers
    - 6.47.5.1 Defining Global Register Variables
    - 6.47.5.2 Specifying Registers for Local Variables
  - 6.47.6 Size of an asm
- 6.48 Alternate Keywords
- 6.49 Incomplete enum Types
- 6.50 Function Names as Strings
- 6.51 Getting the Return or Frame Address of a Function
- 6.52 Using Vector Instructions through Built-in Functions
- 6.53 Support for offsetof
- 6.54 Legacy __sync Built-in Functions for Atomic Memory Access
- 6.55 Built-in Functions for Memory Model Aware Atomic Operations
- 6.56 Built-in Functions to Perform Arithmetic with Overflow Checking
- 6.57 x86-Specific Memory Model Extensions for Transactional Memory
- 6.58 Object Size Checking Built-in Functions
- 6.59 Other Built-in Functions Provided by GCC
- 6.60 Built-in Functions Specific to Particular Target Machines
  - 6.60.1 AArch64 Built-in Functions
  - 6.60.2 Alpha Built-in Functions
  - 6.60.3 Altera Nios II Built-in Functions
  - 6.60.4 ARC Built-in Functions
  - 6.60.5 ARC SIMD Built-in Functions
  - 6.60.6 ARM iWMMXt Built-in Functions
  - 6.60.7 ARM C Language Extensions (ACLE)
  - 6.60.8 ARM Floating Point Status and Control Intrinsics
  - 6.60.9 ARM ARMv8-M Security Extensions
  - 6.60.10 AVR Built-in Functions
  - 6.60.11 Blackfin Built-in Functions
  - 6.60.12 BPF Built-in Functions
  - 6.60.13 FR-V Built-in Functions
    - 6.60.13.1 Argument Types
    - 6.60.13.2 Directly-Mapped Integer Functions
    - 6.60.13.3 Directly-Mapped Media Functions
    - 6.60.13.4 Raw Read/Write Functions
    - 6.60.13.5 Other Built-in Functions
  - 6.60.14 LoongArch Base Built-in Functions
  - 6.60.15 MIPS DSP Built-in Functions
  - 6.60.16 MIPS Paired-Single Support
  - 6.60.17 MIPS Loongson Built-in Functions
    - 6.60.17.1 Paired-Single Arithmetic
    - 6.60.17.2 Paired-Single Built-in Functions
    - 6.60.17.3 MIPS-3D Built-in Functions
  - 6.60.18 MIPS SIMD Architecture (MSA) Support
    - 6.60.18.1 MIPS SIMD Architecture Built-in Functions
  - 6.60.19 Other MIPS Built-in Functions
  - 6.60.20 MSP430 Built-in Functions
  - 6.60.21 NDS32 Built-in Functions
  - 6.60.22 picoChip Built-in Functions
  - 6.60.23 Basic PowerPC Built-in Functions
    - 6.60.23.1 Basic PowerPC Built-in Functions Available on all Configurations
    - 6.60.23.2 Basic PowerPC Built-in Functions Available on ISA 2.05
    - 6.60.23.3 Basic PowerPC Built-in Functions Available on ISA 2.06
    - 6.60.23.4 Basic PowerPC Built-in Functions Available on ISA 2.07
    - 6.60.23.5 Basic PowerPC Built-in Functions Available on ISA 3.0
    - 6.60.23.6 Basic PowerPC Built-in Functions Available on ISA 3.1
  - 6.60.24 PowerPC AltiVec/VSX Built-in Functions
    - 6.60.24.1 PowerPC AltiVec Built-in Functions on ISA 2.05
    - 6.60.24.2 PowerPC AltiVec Built-in Functions Available on ISA 2.06
    - 6.60.24.3 PowerPC AltiVec Built-in Functions Available on ISA 2.07
    - 6.60.24.4 PowerPC AltiVec Built-in Functions Available on ISA 3.0
    - 6.60.24.5 PowerPC AltiVec Built-in Functions Available on ISA 3.1
  - 6.60.25 PowerPC Hardware Transactional Memory Built-in Functions
    - 6.60.25.1 PowerPC HTM Low Level Built-in Functions
    - 6.60.25.2 PowerPC HTM High Level Inline Functions
  - 6.60.26 PowerPC Atomic Memory Operation Functions
  - 6.60.27 PowerPC Matrix-Multiply Assist Built-in Functions
  - 6.60.28 PRU Built-in Functions
  - 6.60.29 RISC-V Built-in Functions
  - 6.60.30 RX Built-in Functions
  - 6.60.31 S/390 System z Built-in Functions
  - 6.60.32 SH Built-in Functions
  - 6.60.33 SPARC VIS Built-in Functions
  - 6.60.34 TI C6X Built-in Functions
  - 6.60.35 TILE-Gx Built-in Functions
  - 6.60.36 TILEPro Built-in Functions
  - 6.60.37 x86 Built-in Functions
  - 6.60.38 x86 Transactional Memory Intrinsics
  - 6.60.39 x86 Control-Flow Protection Intrinsics
- 6.61 Format Checks Specific to Particular Target Machines
  - 6.61.1 Solaris Format Checks
  - 6.61.2 Darwin Format Checks
- 6.62 Pragmas Accepted by GCC
  - 6.62.1 AArch64 Pragmas
  - 6.62.2 ARM Pragmas
  - 6.62.3 M32C Pragmas
  - 6.62.4 MeP Pragmas
  - 6.62.5 PRU Pragmas
  - 6.62.6 RS/6000 and PowerPC Pragmas
  - 6.62.7 S/390 Pragmas
  - 6.62.8 Darwin Pragmas
  - 6.62.9 Solaris Pragmas
  - 6.62.10 Symbol-Renaming Pragmas
  - 6.62.11 Structure-Layout Pragmas
  - 6.62.12 Weak Pragmas
  - 6.62.13 Diagnostic Pragmas
  - 6.62.14 Visibility Pragmas
  - 6.62.15 Push/Pop Macro Pragmas
  - 6.62.16 Function Specific Option Pragmas
  - 6.62.17 Loop-Specific Pragmas
- 6.63 Unnamed Structure and Union Fields
- 6.64 Thread-Local Storage
  - 6.64.1 ISO/IEC 9899:1999 Edits for Thread-Local Storage
  - 6.64.2 ISO/IEC 14882:1998 Edits for Thread-Local Storage
- 6.65 Binary Constants using the ‘0b’ Prefix
7 Extensions to the C++ Language
- 7.1 When is a Volatile C++ Object Accessed?
- 7.2 Restricting Pointer Aliasing
- 7.3 Vague Linkage
- 7.4 C++ Interface and Implementation Pragmas
- 7.5 Where’s the Template?
- 7.6 Extracting the Function Pointer from a Bound Pointer to Member Function
- 7.7 C++-Specific Variable, Function, and Type Attributes
- 7.8 Function Multiversioning
- 7.9 Type Traits
- 7.10 C++ Concepts
- 7.11 Deprecated Features
- 7.12 Backwards Compatibility
8 GNU Objective-C Features
- 8.1 GNU Objective-C Runtime API
  - 8.1.1 Modern GNU Objective-C Runtime API
  - 8.1.2 Traditional GNU Objective-C Runtime API
- 8.2 +load: Executing Code before main
  - 8.2.1 What You Can and Cannot Do in +load
- 8.3 Type Encoding
- 8.4 Garbage Collection
- 8.5 Constant String Objects
- 8.6 compatibility_alias
- 8.7 Exceptions
- 8.8 Synchronization
- 8.9 Fast Enumeration
- 8.10 Messaging with the GNU Objective-C Runtime
  - 8.10.1 Dynamically Registering Methods
  - 8.10.2 Forwarding Hook
9 Binary Compatibility
10 gcov—a Test Coverage Program
- 10.1 Introduction to gcov
- 10.2 Invoking gcov
- 10.3 Using gcov with GCC Optimization
- 10.4 Brief Description of gcov Data Files
- 10.5 Data File Relocation to Support Cross-Profiling
11 gcov-tool—an Offline Gcda Profile Processing Tool
- 11.1 Introduction to gcov-tool
- 11.2 Invoking gcov-tool
12 gcov-dump—an Offline Gcda and Gcno Profile Dump Tool
- 12.1 Introduction to gcov-dump
- 12.2 Invoking gcov-dump
13 lto-dump—Tool for dumping LTO object files.
- 13.1 Introduction to lto-dump
- 13.2 Invoking lto-dump
14 Known Causes of Trouble with GCC
- 14.1 Actual Bugs We Haven’t Fixed Yet
- 14.2 Interoperation
- 14.3 Incompatibilities of GCC
- 14.4 Fixed Header Files
- 14.5 Standard Libraries
- 14.6 Disappointments and Misunderstandings
- 14.7 Common Misunderstandings with GNU C++
- 14.8 Certain Changes We Don’t Want to Make
- 14.9 Warning Messages and Error Messages
15 Reporting Bugs
- 15.1 Have You Found a Bug?
- 15.2 How and Where to Report Bugs
16 How To Get Help with GCC
17 Contributing to GCC Development
Funding Free Software
The GNU Project and GNU/Linux
GNU General Public License
GNU Free Documentation License
- ADDENDUM: How to use this License for your documents
Contributors to GCC
Option Index
Keyword Index

Short Table of Contents

Table of Contents

Introduction ¶