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### 1.56 `sqrt`, `sqrtf`—positive square root

Synopsis

    #include <math.h>
    double sqrt(double x);
    float  sqrtf(float x);

Description
`sqrt` computes the positive square root of the argument. You can modify error handling for this function with `matherr`.

Returns
On success, the square root is returned. If x is real and positive, then the result is positive. If x is real and negative, the global value `errno` is set to `EDOM` (domain error).

Portability
`sqrt` is ANSI C. `sqrtf` is an extension.