Question

Part of my program is to calculate sqrt of float number.
When I write sqrt(1.0f); I success to compile the program,but when I write sqrt(-1.0f);
the compilation fails with undefined reference to 'sqrt' – I suppose that in this case the nan value will be returned…
I compile the program uing gcc.
When I compile it with visual studio it is compiled successfuly with negative argument to sqrt.
How the problem could be solved
Thank you

Answer 1

You have to add the -lm flag on most Unix-based systems, as in:

Compile using:

gcc -c file.c

and then link using:

gcc -o program file.o -lm

Or if you don’t want to separate the two compilation steps, simply write:

gcc -o program file.c -lm