This intrinsic inserts a VFP `VSQRT`

instruction
into the instruction stream generated by the compiler. It enables
you to obtain the square root of a double-precision floating-point
value from within your C or C++ code.

### Note

The `__sqrt`

intrinsic is an analogue of
the standard C library function `sqrt`

. It differs from
the standard library function in that a call to `__sqrt`

is
guaranteed to be compiled into a single, inline, machine instruction
on an ARM architecture-based processor equipped with a VFP coprocessor.

double __sqrt(double `val`

)

Where:

`val`

is a double-precision floating-point value.

The `__sqrt`

intrinsic returns the square
root of `val`

as a double.

The compiler does not recognize the `__sqrt`

intrinsic
when compiling for a target that is not equipped with a VFP coprocessor.
The compiler generates either a warning or an error in this case.