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 |