Compute the argument of a complex number
Synopsis:
#include <complex.h>
double carg(double complex z);
float cargf(float complex z);
long double cargl(long double complex z);
Arguments:
- z
- The complex value that you want to get the argument of.
Library:
- 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.
Description:
These functions compute the argument (or phase angle) 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
carg(), cargf(), or cargl().
- On return, if fetestexcept(FE_ALL_EXCEPT)
is nonzero, then an error has occurred.
Returns:
If no errors occur, the argument of z, in the interval (-π; π).
Errors and special cases are handled as if the function were implemented as
atan2
(cimag(z),
creal(z)).
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 point |
No |
| Interrupt handler |
Yes |
| Signal handler |
Yes |
| Thread |
Yes |