Re: [perl #36654] Inconsistent treatment of NaN

Date: Aug 7, 2005 8:03 PM
Message-ID: <20050807180308.GA2112@efn.org>

Subject: Re: [perl #36654] Inconsistent treatment of NaN
From: Yitzchak Scott-Thoennes <sthoenna@efn.org>
Date: Wed, 10 Aug 2005 22:53:51 -0700
Message-ID: <20050811055351.GA2296@efn.org>

p4raw-id: //depot/perl@25299

diff --git a/numeric.c b/numeric.c
index 3015842..5eafdda 100644 (file)
--- a/numeric.c
+++ b/numeric.c
@@ -893,6 +893,21 @@ Perl_my_atof2(pTHX_ const char* orig, NV* value)
            ++s;
     }
 
+    /* punt to strtod for NaN/Inf; if no support for it there, tough luck */
+
+#ifdef HAS_STRTOD
+    if (*s == 'n' || *s == 'N' || *s == 'i' || *s == 'I') {
+        char *p = negative ? s-1 : s;
+        char *endp;
+        NV rslt;
+        rslt = strtod(p, &endp);
+        if (endp != p) {
+            *value = rslt;
+            return (char *)endp;
+        }
+    }
+#endif
+
     /* we accumulate digits into an integer; when this becomes too
      * large, we add the total to NV and start again */
 

diff --git a/pod/perlop.pod b/pod/perlop.pod
index ba2ff9f..da7cef5 100644 (file)
--- a/pod/perlop.pod
+++ b/pod/perlop.pod
@@ -369,8 +369,8 @@ values, using them with "<=>" returns undef.  NaN is not "<", "==", ">",
 returns true, as does NaN != anything else. If your platform doesn't
 support NaNs then NaN is just a string with numeric value 0.
 
-    perl -le '$a = NaN; print "No NaN support here" if $a == $a'
-    perl -le '$a = NaN; print "NaN support here" if $a != $a'
+    perl -le '$a = "NaN"; print "No NaN support here" if $a == $a'
+    perl -le '$a = "NaN"; print "NaN support here" if $a != $a'
 
 Binary "eq" returns true if the left argument is stringwise equal to
 the right argument.