configure: compile-time word size detection
Signed-off-by: Aaron Carroll <aaronc@cse.unsw.edu.au>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/configure b/configure
index 1fa9b63..84c6af2 100755
--- a/configure
+++ b/configure
@@ -348,16 +348,20 @@
# check for wordsize
wordsize="0"
cat > $TMPC <<EOF
-#include <stdio.h>
+#include <limits.h>
+#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
int main(void)
{
- unsigned int wsize = sizeof(long) * 8;
- printf("%d\n", wsize);
+ BUILD_BUG_ON(sizeof(long)*CHAR_BIT != WORDSIZE);
return 0;
}
EOF
-if compile_prog "" "" "wordsize"; then
- wordsize=`$TMPE`
+if compile_prog "-DWORDSIZE=32" "" "wordsize"; then
+ wordsize="32"
+elif compile_prog "-DWORDSIZE=64" "" "wordsize"; then
+ wordsize="64"
+else
+ fatal "Unknown wordsize"
fi
echo "Wordsize $wordsize"