1 files changed, 22 insertions, 0 deletions
diff --git a/lib/ccan/str/test/compile_fail-islower.c b/lib/ccan/str/test/compile_fail-islower.c
new file mode 100644
index 0000000000..ca3f9907e5
--- /dev/null
+++ b/lib/ccan/str/test/compile_fail-islower.c
@@ -0,0 +1,22 @@
+#define CCAN_STR_DEBUG 1
+#include <ccan/str/str.h>
+
+int main(int argc, char *argv[])
+{
+#ifdef FAIL
+#if !HAVE_BUILTIN_TYPES_COMPATIBLE_P || !HAVE_TYPEOF
+#error We need typeof to check islower.
+#endif
+	char
+#else
+	unsigned char
+#endif
+		c = argv[0][0];
+
+#ifdef FAIL
+	/* Fake fail on unsigned char platforms. */
+	BUILD_ASSERT((char)255 < 0);
+#endif
+
+	return islower(c);
+}