Legacy Document

sqrt

You can use the square root (sqrt) function to compute the square root of a real number.

double_t sqrt(double_t x);

x

Any positive floating-point number.

DESCRIPTION

$sqrt(x)\; =\; SQRTx$

EXCEPTIONS

When x is finite and nonzero, either the result of $sqrt(x)$ is exact or it raises one of the following exceptions:

• inexact (if the result must be rounded)
• invalid (if x is negative)

SPECIAL CASES

Table 6-7 shows the results when the argument to the square root function is a zero, a NaN, or an Infinity, plus other special cases for the square root function. In this table, x is a finite, nonzero floating-point number.

Table 6-7 Special cases for floating-point square root

Operation	Result	Exceptions raised
$sqrt(x)forx0$	NaN	Invalid
$sqrt(+0)$	+0	None
$sqrt(-0)$	$-0$	None
$sqrt(NaN)$	NaN	None[9]
$sqrt(+$ )	+	None
$sqrt(-$ )	NaN	Invalid

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[9] If the NaN is a signaling NaN, the invalid exception is raised.