Isnumeric() ? Check if a string is a number?

There appears to be no isnumeric support, how is everyone validating a string is a number?

There is isdigit() for single characters, or you could just attempt a conversion and check the result, or you use strspn().

It also depends on what you consider numeric, do you want to check for integers, floating point, pure numeric or also starting with a number irrespective of any non-numeric suffix?