[11742] in Athena Bugs
Your OLC question about "c"
daemon@ATHENA.MIT.EDU (wchuang@MIT.EDU)
Mon Feb 14 21:12:26 1994
From: wchuang@MIT.EDU
Date: Mon, 14 Feb 94 21:12:16 -0500
To: "." <bhoffman@MIT.EDU>
Cc: alkarim@MIT.EDU, bugs@MIT.EDU
--------
Hello... I'm sorry I couldn't answer your OLC question before you logged
out. Your question was:
> Hello...is there a bug with the cbrt() math.h function on the DECstation
> s? It's just giving me totally bogus output...here's the code snippit:
>
> fraction = ((12*max_moment)/stress_allow);
> height = cbrt(fraction);
> printf("fraction: %lf",fraction);
> printf("height: %lf",height);
>
> fraction comes out right, but height ends up being like 250 billion something.
> all variables are type double.
> Thanks
The reason this is not working is because the cbrt() function is not
prototyped in the include file math.h. If you add the following to your
C code declarations:
double cbrt(double);
if you are using ANSI style declarations, or:
double cbrt();
if you are using old K&R style declarations, the cbrt() function will
return the correct results. I am also forwarding this question to the
"bugs" mailing list, so that it can be dealt with and fixed in the
future.
I hope this answers your question, and thanks for using OLC!
o William Chuang
o CSS Student Consultant
