csqrt(), csqrtf(), csqrtl()

Compute the square root of a complex number

Synopsis:

#include <complex.h>

double complex csqrt( double complex z );

float complex csqrtf( float complex z );

long double complex csqrtl( long double complex z );

Arguments:

z: The complex value that you want to get the square root of.

Library:

libm: The general-purpose math library.
libm-sve: (QNX Neutrino 7.1 or later) A library that optimizes the code for ARMv8.2 chips that have Scalable Vector Extension hardware.

Your system requirements will determine how you should work with these libraries:

If you want only selected processes to run with the SVE version, you can include both libraries in your OS image and use the -l m or -l m-sve option to qcc to link explicitly against the appropriate one.
If you want all processes to use the SVE version, include libm-sve.so in your OS image and set up a symbolic link from libm.so to libm-sve.so. Use the -l m option to qcc to link against the library.

Note: Compile your program with the -fno-builtin option to prevent the compiler from using a built-in version of the function.

Description:

These functions compute the square root of the complex number specified by z, with a branch cut along the negative real axis.

To check for error situations, use feclearexcept() and fetestexcept(). For example:

Call feclearexcept(FE_ALL_EXCEPT) before calling csqrt(), csqrtf(), or csqrtl().
On return, if fetestexcept(FE_ALL_EXCEPT) is nonzero, then an error has occurred.

Returns:

The square root of z.

If `z` is:	These functions return:	Errors:
±0 + 0`i`	0 + 0`i`	—
`x` + Inf`i`	Inf + Inf`i`, even if `x` is NaN	—
`x` + NaN`i`	NaN + NaN`i`, for finite `x`	—
-Inf + `yi`	0 + Inf`i`, for finite positive `y`	—
Inf + `yi`	Inf + 0`i`, for finite positive `y`	—
-Inf + NaN`i`	NaN ± Inf, where the sign of imaginary part is unspecified	—
Inf + NaN`i`	Inf + NaN`i`	—
NaN + y`i`	NaN + NaN`i`	FE_INVALID
NaN + NaN`i`	NaN + NaN`i`	—

These functions raise FE_INEXACT if the FPU reports that the result can't be exactly represented as a floating-point number.

Classification:

C11, POSIX 1003.1

Safety:
Cancellation point	No
Interrupt handler	Yes
Signal handler	Yes
Thread	Yes