csqrt(), csqrtf(), csqrtl()

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 );


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



Use the -l m option to qcc to link against this library.


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.


ANSI, POSIX 1003.1

Cancellation point No
Interrupt handler No
Signal handler No
Thread Yes