cpow(), cpowf(), cpowl()

QNX SDP8.0C Library ReferenceAPIDeveloper

Raise a complex number to the power of another complex number

Synopsis:

#include <complex.h>

double complex cpow( double complex x,
                     double complex y );

float complex cpowf( float complex x,
                     float complex y );

long double complex cpowl( long double complex x,
                           long double complex y );

Arguments:

x
The number you want to raise.
y
The power you want to raise the number to.

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 complex power function, xy, with a branch cut for the first parameter along the negative real axis.

To check for error situations, use feclearexcept() and fetestexcept(). For example:

  • Call feclearexcept(FE_ALL_EXCEPT) before calling cpow(), cpowf(), or cpowl().
  • On return, if fetestexcept(FE_ALL_EXCEPT) is nonzero, then an error has occurred.

Returns:

The complex power, xy. Errors and special cases are handled as if the operation were implemented as cexp(y * clog(x)).

These functions raise FE_INEXACT if the FPU reports that the result can't be exactly represented as a floating-point number.

Classification:

C11, POSIX 1003.1

Safety:
Cancellation pointNo
Signal handlerYes
ThreadYes
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