.. Copyright 1988-2022 Free Software Foundation, Inc. This is part of the GCC manual. For copying conditions, see the copyright.rst file. .. _environment-implementation: Environment *********** The behavior of most of these points are dependent on the implementation of the C library, and are not defined by GCC itself. * The mapping between physical source file multibyte characters and the source character set in translation phase 1 (C90, C99 and C11 5.1.1.2). See :ref:`cpp:implementation-defined-behavior`.