bizarre math header issue with gnu-c

[simonjester]

I have a weird problem with a simple c program. I have included the math.h file but the function call 'sqrt' is not recognized. I'm not a c newby and I don't get this compile error:

!:>cc tester.c -o tester
tester.c:(.text+0x35): undefined reference to `sqrt'
collect2: ld returned 1 exit status

here is the source

#include <stdio.h>
#include <math.h>

int main ()
{
double param, result;
param = 1024.0;
result = sqrt (param);
printf ("sqrt(%lf) = %lf\n", param, result );
return 0;
}

GCC version on Gutsy

gcc version 4.1.3 20070929 (prerelease)

[snova]

You have to link with the math library. Add '-lm' to the compiler command line.


gcc tester.c -o tester -lm

[simonjester]

That did it.

Thanks.