Fill a few little holes in the math library

1 files changed, 48 insertions, 0 deletions

diff --git a/libm/nan.c b/libm/nan.c
new file mode 100644
index 000000000..8d7998896
--- /dev/null
+++ b/libm/nan.c
@@ -0,0 +1,48 @@
+/***********************************************************************
+    nan, nanf, nanl - return quiet NaN
+
+	These functions shall return a quiet NaN, if available, with content
+	indicated through tagp.
+
+	If the implementation does not support quiet NaNs, these functions
+	shall return zero.
+
+   Calls:  strlen(), sprintf(), strtod()
+
+***********************************************************************/
+#include <math.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+double nan (const char *tagp)
+{
+    if (tagp[0] != '\0') {
+	char buf[6 + strlen (tagp)];
+	sprintf (buf, "NAN(%s)", tagp);
+	return strtod (buf, NULL);
+    }
+    return NAN;
+}
+
+float nanf (const char *tagp)
+{
+    if (tagp[0] != '\0') {
+	char buf[6 + strlen (tagp)];
+	sprintf (buf, "NAN(%s)", tagp);
+	return strtof (buf, NULL);
+    }
+    return NAN;
+}
+
+#if 0
+long double nanl (const char *tagp)
+{
+    if (tagp[0] != '\0') {
+	char buf[6 + strlen (tagp)];
+	sprintf (buf, "NAN(%s)", tagp);
+	return strtold (buf, NULL);
+    }
+    return NAN;
+}
+#endif