Compute the square root of a complex number
#include <complex.h> double complex csqrt( double complex z ); float complex csqrtf( float complex z ); long double complex csqrtl( long double complex z );
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:
The square root of z.
If z is: | These functions return: | Errors: |
---|---|---|
±0 + 0i | 0 + 0i | — |
x + Infi | Inf + Infi, even if x is NaN | — |
x + NaNi | NaN + NaNi, for finite x | — |
-Inf + yi | 0 + Infi, for finite positive y | — |
Inf + yi | Inf + 0i, for finite positive y | — |
-Inf + NaNi | NaN ± Inf, where the sign of imaginary part is unspecified | — |
Inf + NaNi | Inf + NaNi | — |
NaN + yi | NaN + NaNi | FE_INVALID |
NaN + NaNi | NaN + NaNi | — |
These functions raise FE_INEXACT if the FPU reports that the result can't be exactly represented as a floating-point number.
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |