If gcc 4.4.4 is invoked with -maltivec on ppc or ppc64 it predefined 'bool' which gcc 4.3.4 and earlier do not. This causes programs like this which work on 4.3.4 to fail to compile on 4.4.4 #ifndef bool typedef int bool; const bool true = 1; const bool false = 0; #endif int main(int argc,char *argv[]) { bool b = false; return b; } Reproducible: Always Steps to Reproduce: 1. gcc -Wall -maltivec test.c # test code given under description 2. 3. Actual Results: result with 4.4.4 is: test.c: In function main: test.c:8: error: bool undeclared (first use in this function) test.c:8: error: (Each undeclared identifier is reported only once test.c:8: error: for each function it appears in.) test.c:8: error: expected ; before b test.c:9: error: b undeclared (first use in this function) Expected Results: with gcc 4.3.4 test code compiles and works fine the problem can be seen by printing the predefined macros thusly: $ touch /tmp/empty.c && /usr/powerpc64-unknown-linux-gnu/gcc-bin/4.4.4/powerpc64-unknown-linux-gnu-cpp -dM -maltivec /tmp/empty.c | grep bool #define bool bool #define __bool __attribute__((altivec(bool__))) unsigned $ touch /tmp/empty.c && /usr/powerpc64-unknown-linux-gnu/gcc-bin/4.3.4/powerpc64-unknown-linux-gnu-cpp -dM -maltivec /tmp/empty.c | grep bool #define __bool __attribute__((altivec(bool__))) unsigned
On further study this seems to be a feature and not a bug info gcc for 4.3.4 says: * Compiling with `-maltivec' adds keywords `__vector', `__pixel', and `__bool'. Macros `vector', `pixel', and `bool' are defined in `<altivec.h>' and can be undefined. info gcc 4.4.4 has been changed to say: * Compiling with `-maltivec' adds keywords `__vector', `vector', `__pixel', `pixel', `__bool' and `bool'. When compiling ISO C, the context-sensitive substitution of the keywords `vector', `pixel' and `bool' is disabled. To use them, you must include `<altivec.h>' instead. So I guess code using the (now) keyword 'bool' (or 'vector' or 'pixel') needs to be changed to comply with compiler change in 4.4.4 or the option -maltivec should not be applied during compilation
include <stdbool.h> if you want to use "bool"
