接口定义

C interface：

float complex catanf(float complex x);

double complex catan(double complex x);

long double complex catanl(long double complex x);

参数

参数名	类型	描述	输入/输出
x	在catanf中，x是复数单精度浮点类型。在catan中，x是复数双精度浮点类型。在catanl中，x是复数长双精度浮点类型。	表示输入数据的浮点值。	输入

返回值

返回x的反正切结果y。

特殊值说明如下所示。

输入值实部（x.real）	输入值虚部（x.imag）	输出值实部（y.real）	输出值虚部（y.imag）
-inf	-inf	-pi/2	-0.0
-inf	< +0.0	-pi/2	-0.0
-inf	-0.0	-pi/2	-0.0
-inf	+0.0	-pi/2	+0.0
-inf	> +0.0	-pi/2	+0.0
-inf	inf	-pi/2	+0.0
-inf	-nan	-pi/2	+0.0
-inf	nan	-pi/2	+0.0
< +0.0	-inf	-pi/2	-0.0
< +0.0	inf	-pi/2	+0.0
< +0.0	-nan	nan	nan
< +0.0	nan	nan	nan
-0.0	-inf	-pi/2	-0.0
-0.0	-0.0	-0.0	-0.0
-0.0	+0.0	-0.0	0.0
-0.0	inf	-pi/2	+0.0
-0.0	-nan	nan	nan
-0.0	nan	nan	nan
+0.0	-inf	pi/2	-0.0
+0.0	-0.0	+0.0	-0.0
+0.0	+0.0	+0.0	+0.0
+0.0	inf	pi/2	+0.0
+0.0	-nan	nan	nan
+0.0	nan	nan	nan
> +0.0	-inf	pi/2	-0.0
> +0.0	inf	pi/2	+0.0
> +0.0	-nan	nan	nan
> +0.0	nan	nan	nan
inf	-inf	pi/2	-0.0
inf	< +0.0	pi/2	-0.0
inf	-0.0	pi/2	-0.0
inf	+0.0	pi/2	+0.0
inf	> +0.0	pi/2	+0.0
inf	inf	pi/2	+0.0
inf	-nan	pi/2	+0.0
inf	nan	pi/2	+0.0
-nan	-inf	nan	-0.0
-nan	< +0.0	nan	nan
-nan	-0.0	nan	-0.0
-nan	+0.0	nan	+0.0
-nan	> +0.0	nan	nan
-nan	inf	nan	+0.0
-nan	-nan	nan	nan
-nan	nan	nan	nan
nan	-inf	nan	-0.0
nan	< +0.0	nan	nan
nan	-0.0	nan	-0.0
nan	+0.0	nan	+0.0
nan	> +0.0	nan	nan
nan	inf	nan	+0.0
nan	-nan	nan	nan
nan	nan	nan	nan

依赖

C: "km.h"

示例

C interface：

    // typical usage
    double x1 = 1.0, x2 = 2.0, x3 = 3.0, x4 = 4.0;
    double complex cx1 = __builtin_complex(x1, x2);
    double complex cx2 = __builtin_complex(x3, x4);
    double complex cx3 = __builtin_complex(NAN, NAN);
    double complex cx4 = __builtin_complex(INFINITY, -INFINITY);
    double ry;
    double iy;
    ry = __real__ catan(cx1);
    iy = __imag__ catan(cx1);
    printf("catan(cx1) = %.15f, %.15f\n", ry, iy);
    ry = __real__ catan(cx2);
    iy = __imag__ catan(cx2);
    printf("catan(cx2) = %.15f, %.15f\n", ry, iy);
    ry = __real__ catan(cx3);
    iy = __imag__ catan(cx3);
    printf("catan(cx3) = %.15f, %.15f\n", ry, iy);
    ry = __real__ catan(cx4);
    iy = __imag__ catan(cx4);
    printf("catan(cx4) = %.15f, %.15f\n", ry, iy);

result:
   /*
    * catan(cx1) = 1.338972522294493, 0.402359478108525
    * catan(cx2) = 1.448306995231464, 0.158997191679999
    * catan(cx3) = nan, nan
    * catan(cx4) = 1.570796326794897, -0.000000000000000
    */