The option `-traditional
' disables certain keywords; `-ansi
'
disables certain others. This causes trouble when you want to use GNU C
extensions, or ANSI C features, in a general-purpose header file that
should be usable by all programs, including ANSI C programs and traditional
ones. The keywords asm
, typeof
and inline
cannot be
used since they won't work in a program compiled with `-ansi
', while
the keywords const
, volatile
, signed
, typeof
and inline
won't work in a program compiled with
`-traditional
'.
The way to solve these problems is to put `__
' at the beginning and
end of each problematical keyword. For example, use __asm__
instead of asm
, __const__
instead of const
, and
__inline__
instead of inline
.
Other C compilers won't accept these alternative keywords; if you want to compile with another compiler, you can define the alternate keywords as macros to replace them with the customary keywords. It looks like this:
#ifndef __GNUC__ #define __asm__ asm #endif
`-pedantic
' causes warnings for many GNU C extensions. You can
prevent such warnings within one expression by writing
__extension__
before the expression. __extension__
has no
effect aside from this.