c/keyword

This is a list of reserved keywords in C. Since they are used by the language, these keywords are not available for re-definition.

The most common keywords that begin with an underscore are generally used through their convenience macros:

Also, each name that begins with a double underscore or an underscore  followed by an uppercase letter is reserved: see identifier for details.

Note that digraphs, , , , , and provide an alternative way to represent standard tokens.

The following tokens are recognized by the preprocessor when they are used within the context of a preprocessor directive:

The following tokens are recognized by the preprocessor when they are used outside the context of a preprocessor directive:

The following additional keywords are classified as extensions and conditionally-supported: