Updated: April 19, 2023 |

*Compute the square root of a complex number*

#include <complex.h> double complex csqrt( double complexz); float complex csqrtf( float complexz); long double complex csqrtl( long double complexz);

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

- 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.

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.

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 | Yes |

Signal handler | Yes |

Thread | Yes |