why i cant use abs() ? and what should i do?

everyone . I'm trying to use abs(), but my ide says:

"abs" is ambiguous

Here's my code :

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    double x = -87.91, result;
    result = abs(x);
    cout<<result;
    return 0;
}

What should I do to fix that?

I tried to to use fabs(), but that's not what I need.