gistfile1.txt

--- hash.c~	Tue Mar 08 23:06:17 2011
+++ hash.c	Sat Mar 19 17:24:57 2011
@@ -2194,6 +2194,20 @@ envix(const char *nam)
 }
 #endif
 
+#if defined(_WIN32)
+static int
+getenvsize(char* p)
+{
+    char prev = *p++;
+    int len = 1;
+    for (; prev || *p; p++) {
+        prev = *p;
+        len++;
+    }
+    return len;
+}
+#endif
+
 void
 ruby_setenv(const char *name, const char *value)
 {
@@ -2206,7 +2220,12 @@ ruby_setenv(const char *name, const char
 	rb_sys_fail("ruby_setenv");
     }
     if (value) {
-	if (strlen(value) > 5120) goto fail;
+	char* p = GetEnvironmentStringsA();
+	if (p) {
+            if (strlen(value) + getenvsize(p) >= 32767) goto fail;
+	} else {
+	    if (strlen(value) >= 5120) goto fail;
+	}
 	buf = rb_sprintf("%s=%s", name, value);
     }
     else {