busybox.h includes config.h before anything else.
config.h defines or undefines various CONFIG_FOO macros depending on which parts of BusyBox are to be built.
Some of these macros conflict with similarly-named macros defined in <linux/autoconf.h> which is pulled in indirectly by <limits.h> and / or <sys/param.h> near the bottom of busybox.h.
This can lead to a build failure in applets.c. Let's say you want to build busybox without the sysctl applet, so config.h contains #undef CONFIG_SYSCTL.
applets.c includes busybox.h
busybox.h includes config.h -> #undef CONFIG_SYSCTL
busybox.h defines PROTOTYPES and includes applets.h
busybox.h includes <sys/param.h> -> #define CONFIG_SYSCTL 1
applets.c defines MAKE_USAGE and includes applets.h
applets.c undefines PROTOTYPES and MAKE_USAGE and includes applets.h to generate the applets[] array
applets[] references an undeclared and undefined sysctl_main() -> BOOM
1) reorders includes in busybox.h to avoid the issue described above
2) moves #include <features.h> to the top of busybox.h (it has to be at the top to correctly affect visibility of identifiers declared by other headers)
3) makes a few adjustments to applets.h to simplify its usage
4) removes a few #undefs made redundant by 3) from applets.c
applets.diff [^] (2,655 bytes) 09-06-05 04:36 
