Keil Logo

Technical Support

On-Line Manuals

Compiler User Guide

Preface Overview of the Compiler Getting Started with the Compiler Compiler Features Compiler Coding Practices Compiler Diagnostic Messages Using the Inline and Embedded Assemblers of the AR Compiler Command-line Options Language Extensions Preprocessor extensions #assert #include_next #unassert #warning C99 language features available in C90 // comments Subscripting struct Flexible array members C99 language features available in C++ and C90 Variadic macros long long restrict Hexadecimal floats Standard C language extensions Constant expressions Array and pointer extensions Block scope function declarations Dollar signs in identifiers Top-level declarations Benign redeclarations External entities Function prototypes Standard C++ language extensions ? operator Declaration of a class member friend Read/write constants Scalar type constants Specialization of nonmember function templates Type conversions Standard C and Standard C++ language extensions Address of a register variable Arguments to functions Anonymous classes, structures and unions Assembler labels Empty declaration Hexadecimal floating-point constants Incomplete enums Integral type extensions Label definitions Long float Nonstatic local variables Structure, union, enum, and bitfield extensions GNU extensions to the C and C++ languages Compiler-specific Features C and C++ Implementation Details What is Semihosting? Via File Syntax Summary Table of GNU Language Extensions Standard C Implementation Definition Standard C++ Implementation Definition C and C++ Compiler Implementation Limits

C99 language features available in C++ and C90

8.10 C99 language features available in C++ and C90

The compiler supports numerous extensions to the ISO C++ standard and to the C90 language, for example, function prototypes that override old-style nonprototype definitions.

These extensions are available if:
  • The source language is C++ and you are compiling in nonstrict mode.
  • The source language is C90 and you are compiling in nonstrict mode.
These extensions are not available if:
  • The source language is C++ and the compiler is restricted to compiling strict Standard C++ using the --strict compiler option.
  • The source language is C90 and the compiler is restricted to compiling strict Standard C using the --strict compiler option.

Note

Language features of Standard C, for example long long integers, might be similar to the C++ and C90 language extensions. Such features continue to remain available if you are compiling strict Standard C++ or strict C90 using the --strict compiler option.
Non-ConfidentialPDF file icon PDF versionARM DUI0375H
Copyright © 2007, 2008, 2011, 2012, 2014-2016 ARM. All rights reserved. 
  Arm logo
Important information

This site uses cookies to store information on your computer. By continuing to use our site, you consent to our cookies.

Change Settings

Privacy Policy Update

Arm’s Privacy Policy has been updated. By continuing to use our site, you consent to Arm’s Privacy Policy. Please review our Privacy Policy to learn more about our collection, use and transfers
of your data.