cpp: Traditional miscellany
1
1 10.3 Traditional miscellany
1 ===========================
1
1 Here are some things to be aware of when using the traditional
1 preprocessor.
1
1 * Preprocessing directives are recognized only when their leading '#'
1 appears in the first column. There can be no whitespace between
1 the beginning of the line and the '#', but whitespace can follow
1 the '#'.
1
1 * A true traditional C preprocessor does not recognize '#error' or
1 '#pragma', and may not recognize '#elif'. CPP supports all the
1 directives in traditional mode that it supports in ISO mode,
1 including extensions, with the exception that the effects of
1 '#pragma GCC poison' are undefined.
1
1 * __STDC__ is not defined.
1
1 * If you use digraphs the behavior is undefined.
1
1 * If a line that looks like a directive appears within macro
1 arguments, the behavior is undefined.
1