B.2.63 -X[c|a|t|s]

The -X (note uppercase X) options specify varying degrees of compliance to the ISO C standard. The value of -xc99 affects which version of the ISO C standard the -X option applies. The -xc99 option defaults to -xc99=all which supports the 1999 ISO/IEC C standard. -xc99=none supports the 1990 ISO/IEC C standard. See Table C–6 for a discussion of supported 1999 ISO/IEC features. See G.2 The libfast.a Library for a discussion of differences between ISO/IEC C and K&R C.

The default mode is -Xa.

-Xc

(c = conformance) Issues errors and warnings for programs that use non-ISO C constructs. This option is strictly conformant ISO C, without K&R C compatibility extensions. The predefined macro __STDC__ has a value of 1 with the-Xc option.

-Xa

This is the default compiler mode. ISO C plus K&R C compatibility extensions, with semantic changes required by ISO C. Where K&R C and ISO C specify different semantics for the same construct, the compiler uses the ISO C interpretation. If the -Xa option is used in conjunction with the -xtransition option, the compiler issues warnings about the different semantics. The predefined macro __STDC__has a value of -0 with the-Xa option.

-Xt

(t = transition) This option uses ISO C plus K&R C compatibility extensions without semantic changes required by ISO C. Where K&R C and ISO C specify different semantics for the same construct, the compiler uses the K&R C interpretation. If you use the -Xt option in conjunction with the -xtransition option, the compiler issues warnings about the different semantics. The predefined macro __STDC__ has a value of 0 with the -Xt option.

-Xs

(s = K&R C) Attempts to warn about all language constructs that have differing behavior between ISO C and K&R C. The compiler language includes all features compatible with K&R C. This option invokes cpp for preprocessing. __STDC__ is not defined in this mode.