csqrt(), csqrtf(), csqrtl()
QNX SDP8.0C Library ReferenceAPIDeveloper
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
- 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 + 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.
Classification:
| Safety: | |
|---|---|
| Cancellation point | No |
| Signal handler | Yes |
| Thread | Yes |
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