What is the Default C Standard Used by g ?

Default C Standard in g

When compiling code with g , a C compiler, it's essential to know the default standard used. By understanding the default standard, you can ensure your code compiles and functions correctly.

Identifying the Default Standard

To identify the default C standard used by g , execute the following command:

g++ -dM -E -x c++ /dev/null | grep -F __cplusplus

This command outputs a macro definition that indicates the value of __cplusplus, which corresponds to the supported C standard version. For example, a result like #define __cplusplus 199711L indicates C 98.

Default Standard Activation

In g versions earlier than 4.7, the default standard is C 98. However, in later versions, the default standard is determined by the compiler flags. If no standard is specified, it defaults to C 98.

Recommended Standard Specification

It's generally recommended to explicitly specify the C standard when compiling code. By using the -std flag, you can set the desired standard, ensuring compatibility with your code's requirements.

For instance, if your code requires C 17 features, it's prudent to use the g -std=c 17 command, as illustrated in the example provided. This approach ensures that the code is compiled and linked properly.

By understanding the default C standard in g and the recommendation to explicitly specify the standard, you can ensure your code compiles successfully and behaves as intended.

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