hush/include/platform.h
Rob Landley 7bfa88f315 New USE() macros
For each CONFIG_SYMBOL, include/bb_config.h now has both ENABLE_SYMBOL
and USE_SYMBOL(x).  ENABLE_SYMBOL is still always defined (1 or 0) so that
if(ENABLE) should optimize out when it's zero.  The USE_SYMBOL(X) will only
splice in X if the symbol is defined, otherwise it'll be empty.

Thus we can convert this:

#ifdef CONFIG_ARGS
    opt = bb_getopt_ulflags(argc, argv, "ab:c"
#ifdef CONFIG_THINGY
        "d:"
#endif
        , &bvalue
#ifdef CONFIG_THINGY
        , &thingy
#endif
    );
#endif

into this:
    if (ENABLE_ARGS) {
        opt = bb_getopt_ulflags(argc, argv, "ab:c" USE_THINGY("d:"), &bvalue
                USE_THINGY(, &thingy));
    }

And it should produce the same code.

Unlike the old versions in include/_usage.h, the new USE_SYMBOL(x) can handle
commas in its arguments (as shown above).  (The _usage.h file is obsolete and
no longer generated.)

Nobody should need to include config.h directly anymore, bb_config.h should
define all the configuration stuff we need.  Someday, the CONFIG_SYMBOL
versions should go away in favor of ENABLE_SYMBOL and USE_SYMBOL().

Thanks to vodz for the new version of bb_mkdep.c that works with function
macros.
2006-02-13 19:16:41 +00:00

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C

/*
Copyright 2006, Bernhard Fischer
Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
*/
#ifndef __PLATFORM_H
#define __PLATFORM_H 1
/* Convenience macros to test the version of gcc. */
#undef __GNUC_PREREQ
#if defined __GNUC__ && defined __GNUC_MINOR__
# define __GNUC_PREREQ(maj, min) \
((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
#else
# define __GNUC_PREREQ(maj, min) 0
#endif
/* __restrict is known in EGCS 1.2 and above. */
#if !__GNUC_PREREQ (2,92)
# ifndef __restrict
# define __restrict /* Ignore */
# endif
#endif
/* Define macros for some gcc attributes. This permits us to use the
macros freely, and know that they will come into play for the
version of gcc in which they are supported. */
#if !__GNUC_PREREQ (2,7)
# ifndef __attribute__
# define __attribute__(x)
# endif
#endif
#if 0
/* Attribute __malloc__ on functions was valid as of gcc 2.96. */
#ifndef ATTRIBUTE_MALLOC
# if __GNUC_PREREQ (2,96)
# define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
# else
# define ATTRIBUTE_MALLOC
# endif /* GNUC >= 2.96 */
#endif /* ATTRIBUTE_MALLOC */
#endif
#ifndef ATTRIBUTE_UNUSED
#define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
#endif /* ATTRIBUTE_UNUSED */
#ifndef ATTRIBUTE_NORETURN
#define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
#endif /* ATTRIBUTE_NORETURN */
#ifndef ATTRIBUTE_PACKED
#define ATTRIBUTE_PACKED __attribute__ ((__packed__))
#endif /* ATTRIBUTE_NORETURN */
#ifndef ATTRIBUTE_ALIGNED
#define ATTRIBUTE_ALIGNED(m) __attribute__ ((__aligned__(m)))
#endif /* ATTRIBUTE_ALIGNED */
/* -fwhole-program makes all symbols local. The attribute externally_visible
forces a symbol global. */
#ifndef ATTRIBUTE_EXTERNALLY_VISIBLE
# if __GNUC_PREREQ (4,1)
# define ATTRIBUTE_EXTERNALLY_VISIBLE __attribute__ ((__externally_visible__))
# else
# define ATTRIBUTE_EXTERNALLY_VISIBLE
# endif /* GNUC >= 4.1 */
#endif /* ATTRIBUTE_EXTERNALLY_VISIBLE */
/* We use __extension__ in some places to suppress -pedantic warnings
about GCC extensions. This feature didn't work properly before
gcc 2.8. */
#if !__GNUC_PREREQ (2,8)
# ifndef __extension__
# define __extension__
# endif
#endif
#endif /* platform.h */