How Can I Determine the Implemented C Standard Version of My Compiler?

Determining the Implemented C Standard Version

Determining the C standard implementation of your compiler can be crucial for ensuring compatibility and utilizing the latest language features. Several C standards have been released, including C 98 and C 03.

One method for identifying the standard version is to check the macro __cplusplus.

__cplusplus Macro

According to Bjarne Stroustrup's C 0x FAQ, the __cplusplus macro will be set to a value greater than 199711L for C 11 and higher. However, some compilers may not set this macro correctly.

GCC

gcc has a history of setting __cplusplus to 1, regardless of the language version. This issue was addressed in gcc 4.7.0.

MSVC

MSVC also incorrectly defines __cplusplus as 199711L. To obtain the correct value, either add /Zc:__cplusplus to compiler flags or check the MSVC-specific macro _MSVC_LANG.

Expected __cplusplus Values

• C pre-C 98: 1
• C 98: 199711L
• C 98 TR1: Cannot be determined using __cplusplus
• C 11: 201103L
• C 14: 201402L
• C 17: 201703L
• C 20: 202002L
• C 23: 202302L

Other Methods

If __cplusplus is insufficient or unavailable, other approaches include:

• Compiler-specific macros: Inspecting compiler-defined macros may reveal the implemented standard version.
• Boost.Config: This library provides macros for checkingspecificC features.
• Feature evaluation: Running code that utilizes specific features can determine their availability and, consequently, the implemented standard version.

It's important to note that not all compilers fully implement all features of a C standard. Careful examination of compiler compatibility and feature support is necessary to ensure reliable code execution.

The above is the detailed content of How Can I Determine the Implemented C Standard Version of My Compiler?. For more information, please follow other related articles on the PHP Chinese website!