sqrt, sqrtf, sqrtl - square root function
#include <math.h>
double sqrt(double x);
float sqrtf(float x);
long double sqrtl(long double x);Link with -lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
sqrtf(), sqrtl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
These functions return the nonnegative square root of x.
On success, these functions return the square root of x.
If x is a NaN, a NaN is returned.
If x is +0 (-0), +0 (-0) is returned.
If x is positive infinity, positive infinity is returned.
If x is less than -0, a domain error occurs, and a NaN is returned.
See math_error(7) for information on how to determine whether an error has occurred when calling these functions.
The following errors can occur:
errno is set to EDOM. An invalid floating-point exception (FE_INVALID) is raised.
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
| sqrt(), sqrtf(), sqrtl() | Thread safety | MT-Safe |
C99, POSIX.1-2001, POSIX.1-2008.
The variant returning double also conforms to SVr4, 4.3BSD, C89.
cbrt(3), csqrt(3), hypot(3)
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