carg, cargf, cargl — complex argument functions
#include <complex.h>
double carg(double complex z);
float cargf(float complex z);
long double cargl(long double complex z);
[CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2024 defers to the ISO C standard.These functions shall compute the argument (also called phase angle) of z, with a branch cut along the negative real axis.
These functions shall return the value of the argument in the interval [-ℼ, +ℼ].
[MXC] If z is -0 ± i0, ±ℼ shall be returned.
If z is +0 ± i0, ±0 shall be returned.
If z is x ± i0 where x is negative, ±ℼ shall be returned.
If z is x ± i0 where x is positive, ±0 shall be returned.
If z is ±0 + iy where y is negative, -ℼ/2 shall be returned.
If z is ±0 + iy where y is positive, ℼ/2 shall be returned.
If z is -Inf ± iy where y is positive and finite, ±ℼ shall be returned.
If z is +Inf ± iy where y is positive and finite, ±0 shall be returned.
If z is x ± iInf where x is finite, ±ℼ/2 shall be returned.
If z is -Inf ± iInf, ±3ℼ/4 shall be returned.
If z is +Inf ± iInf, ±ℼ/4 shall be returned.
If the real or imaginary part of z is NaN, NaN shall be returned.
No errors are defined.
None.
None.
None.
None.
XBD <complex.h>
First released in Issue 6. Derived from the ISO/IEC 9899:1999 standard.
Austin Group Defect 1302 is applied, aligning these functions with the ISO/IEC 9899:2018 standard.
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