Fresh start

1 files changed, 32 insertions, 0 deletions

diff --git a/jni/ruby/missing/isnan.c b/jni/ruby/missing/isnan.c
new file mode 100644
index 0000000..ed10bf5
--- /dev/null
+++ b/jni/ruby/missing/isnan.c
@@ -0,0 +1,32 @@
+/* public domain rewrite of isnan(3) */
+
+#include "ruby/missing.h"
+
+/*
+ * isnan() may be a macro, a function or both.
+ * (The C99 standard defines that isnan() is a macro, though.)
+ * http://www.gnu.org/software/automake/manual/autoconf/Function-Portability.html
+ *
+ * macro only: uClibc
+ * both: GNU libc
+ *
+ * This file is compile if no isnan() function is available.
+ * (autoconf AC_REPLACE_FUNCS detects only the function.)
+ * The macro is detected by following #ifndef.
+ */
+
+#ifndef isnan
+static int double_ne(double n1, double n2);
+
+int
+isnan(double n)
+{
+    return double_ne(n, n);
+}
+
+static int
+double_ne(double n1, double n2)
+{
+    return n1 != n2;
+}
+#endif