1 files changed, 28 insertions, 0 deletions

diff --git a/missing/nan.c b/missing/nan.c
new file mode 100644
index 0000000000..686c48a336
--- /dev/null
+++ b/missing/nan.c
@@ -0,0 +1,28 @@
+#include "ruby/missing.h"
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+double
+nan(const char *spec)
+{
+#if 0
+    /* FIXME: we have not yet seen any situation this is
+     * necessary. Please write a proper implementation that
+     * covers this branch.  */
+    if (spec && spec[0]) {
+	double generated_nan;
+	int len = snprintf(NULL, 0, "NAN(%s)", spec);
+	char *buf = malloc(len + 1); /* +1 for NUL */
+	sprintf(buf, "NAN(%s)", spec);
+	generated_nan = strtod(buf, NULL);
+	free(buf);
+	return generated_nan;
+    }
+    else
+#endif
+    {
+	assert(!spec || !spec[0]);
+	return (double)NAN;
+    }
+}