> On Oct 23, 2017, at 12:09 PM, Stefan Hajnoczi <stefa...@gmail.com> wrote: > > On Sun, Oct 22, 2017 at 10:50:16PM -0400, John Arbuckle wrote: >> Prior the Mac OS 10.7, the function strnlen() was not available. This patch >> implements strnlen() on Mac OS X versions that are below 10.7. >> >> Signed-off-by: John Arbuckle <programmingk...@gmail.com> >> --- >> v3 changes: >> - Replaced loop with memchr() >> >> v2 changes: >> - Simplified the code to make it static inline'ed >> - Changed the type of count to size_t >> >> libfdt/libfdt_env.h | 24 ++++++++++++++++++++++++ >> 1 file changed, 24 insertions(+) >> >> diff --git a/libfdt/libfdt_env.h b/libfdt/libfdt_env.h >> index 952056c..d43b66b 100644 >> --- a/libfdt/libfdt_env.h >> +++ b/libfdt/libfdt_env.h >> @@ -109,4 +109,28 @@ static inline fdt64_t cpu_to_fdt64(uint64_t x) >> #undef CPU_TO_FDT16 >> #undef EXTRACT_BYTE >> >> +#ifdef __APPLE__ >> +#include <AvailabilityMacros.h> >> + >> +#define MAC_OS_X_VERSION_10_7 1070 > > Apple has already defined MAC_OS_X_VERSION_10_7 here: > https://opensource.apple.com/source/xnu/xnu-1699.24.8/EXTERNAL_HEADERS/AvailabilityMacros.h > > To avoid a compiler warning, please use: > > #ifndef MAC_OS_X_VERSION_10_7 > #define MAC_OS_X_VERSION_10_7 1070 > #endif
Sounds logical. > >> +/* strnlen() is not available on Mac OS < 10.7 */ >> +# if (MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7) > > Does this cover the case where MAC_OS_X_VERSION_MAX_ALLOWED is set to > <1070 on a 10.7+ build machine? It's possible that the <string.h> > header would define strnlen() and your code redefines the function > (compiler error). If MAC_OS_X_VERSION_MAX_ALLOWED is equal to 1070 then this code would not be executed. This branch would only be taken if MAC_OS_X_VERSION_MAX_ALLOWED is less than 1070. So there would not be a compiler error. > > It would be best to check how <string.h>, <Availability.h>, and > <AvailabilityMacros.h> work to make sure that all cases are handled. I > don't have access to a Mac right now, sorry. > > Perhaps this approach works better: > > # ifndef MAC_OS_X_VERSION_10_7 I think you are saying I should remove the "#ifdef __APPLE__" code and just check to see if MAC_OS_X_VERSION_10_7 is defined. That might work on Mac OS 10.6 and 10.5, but it would probably cause problems with non-Mac-OS platforms.
