C11 Support in Intel C++ Compiler

By Jennifer L Jiang, Anoop Madhusoodhanan Prabha

Published:08/26/2014   Last Updated:09/12/2017

The following C11 features are supported by Intel(R) C++ compiler that comes with Intel® Parallel Studio XE and Intel® System Studio.

C11 Language Feature Version 15.0 Version 16.0 Version 17.0 Version 18.0
Static Assert Yes Yes Yes Yes
Typedef redefinition - Yes Yes Yes
Anonymous struct and union - Yes Yes Yes
New macros in float.h - Yes Yes Yes
_Alignas, _Alignof,max_align_t,stdalign.h - Yes Yes Yes
_Atomic - - - Yes
Atomic operations - Yes Yes Yes
Macros for Complex values - Yes Yes Yes
Unicode strings - Yes Yes Yes
uchar.h - - - -
_Noreturn,stdnoreturn.h - Yes Yes Yes
_Generic - Yes Yes Yes
__STDC_VERSION__ == 201112L - Yes Yes Yes
_thread_local - Yes Yes Yes


1. The C11 features are only supported when GNU* gcc in path is 4.6 or higher.
2. On Linux: The C11 features supported by gcc on the path are enabled by default. Use "-std=c11" or "-std=c1x" to turn on the support for all other cases.
3. On macOS*: The C11 features supported by gcc on the path are enabled by default. Use "-std=c11" to turn on the support for all other cases.
4. On Windows: The C11 features can be enabled on Windows using "/Qstd=c11" compiler option

Other relevant articles:

GNU GCC C11 support status: https://gcc.gnu.org/wiki/C11Status 
GNU GCC C99 support status: https://gcc.gnu.org/c99status.html
Intel Compiler C99 support status: /content/www/us/en/develop/articles/c99-support-in-intel-c-compiler.html


Product and Performance Information


Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804