3.3.3 Selecting specific standards

The specific language standard used by GCC can be controlled with the -std option. The following C language standards are supported:

-std=c89 or -std=iso9899:1990

The original ANSI/ISO C language standard (ANSI X3.159-1989, ISO/IEC 9899:1990). GCC incorporates the corrections in the two ISO Technical Corrigenda to the original standard.

-std=iso9899:199409

The ISO C language standard with ISO Amendment 1, published in 1994. This amendment was mainly concerned with internationalization, such as adding support for multibyte characters to the C library.

-std=c99 or -std=iso9899:1999

The revised ISO C language standard, published in 1999 (ISO/IEC 9899:1999).

The C language standards with GNU extensions can be selected with the options -std=gnu89 and -std=gnu99.