--- frequency2temperature.comp.orig     2012-12-12 17:53:57.870992519 +0000
+++ frequency2temperature.comp  2012-12-12 17:55:03.843331287 +0000
@@ -11,6 +11,8 @@

 #include <rtapi_math.h> /* exp() and ln() */

+extern double log(double);
+
 /* see http://en.wikipedia.org/wiki/Thermistor
    The B-parameter equation is:
    1/T = 1/T0 + 1/B * ln(R/R0)
@@ -50,18 +52,20 @@
 const double R1 = 3500;

 float thermistor2temperature(float R) {
+   float T;
    if (R<=0)
        R=0.001; // avoid log(0)
-   float T = 1.0/ ( 1.0/T0 + (1.0/B) * log(R/R0) );
+   T = 1.0/ ( 1.0/T0 + (1.0/B) * log(R/R0) );
    return T;
 }

 float frequency2temperature(double f) {
+    float R, T;
     if (f<=0)
         f=1;
-    float R = 0.5 * ( (1.0/(f*0.6931*C1)) - R1);
+    R = 0.5 * ( (1.0/(f*0.6931*C1)) - R1);

-    float T = thermistor2temperature(R);
+    T = thermistor2temperature(R);
     return T;
 }