sqrtf function alternative in Visual Studio

I am writing a project in Visual Studio then I use GCC in order to compile it. Sometimes it causes some problems: This time I cannot use sqrtf function because VS accepts it however GCC does not. So I need to find some way (maybe mathematical approach to calculate square root) to find square root of some number in a way both GCC and VS will accept. To be more precise this is the line which causes a problem:

float x_f = circleRadius - sqrtf((float)((circleRadius * circleRadius) - (y * y)));

I need to find the square root of (circleRadius^2 - y^2)