> For the complete documentation index, see [llms.txt](https://book.bsdcn.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://book.bsdcn.org/man/misc/tgmath.3.md).

# tgmath.3

`tgmath` — 类型通用宏

## 名称

`tgmath`

## 概要

```c
#include <tgmath.h>
```

## 描述

头文件

```c
#include <tgmath.h>
```

为

```c
#include <math.h>
```

和

```c
#include <complex.h>
```

中具有 `float`（后缀为 **f**）、`double` 和 `long double`（后缀为 **l**）版本的函数提供类型通用宏。在三种函数中各不相同且类型分别为 `float`、`double` 和 `long double` 的参数称为*通用参数*。

以下规则描述了调用类型通用宏时实际调用的函数。如果任何通用参数的类型为 `long double` 或 `long double complex`，则调用 `long double` 函数。否则，如果任何通用参数的类型为 `double`、`double complex` 或整数类型，则调用 `double` 版本。否则，宏展开为 `float` 实现。

对于下表中的宏，同时存在实数和复数函数。实数函数的原型在

```c
#include <math.h>
```

中，复数等效函数在

```c
#include <complex.h>
```

中。如果任何通用参数是复数值，则调用复数函数。否则，调用实数等效函数。

| **宏**     | **实数函数**  | **复数函数**   |
| --------- | --------- | ---------- |
| `acos()`  | `acos()`  | `cacos()`  |
| `asin()`  | `asin()`  | `casin()`  |
| `atan()`  | `atan()`  | `catan()`  |
| `acosh()` | `acosh()` | `cacosh()` |
| `asinh()` | `asinh()` | `casinh()` |
| `atanh()` | `atanh()` | `catanh()` |
| `cos()`   | `cos()`   | `ccos()`   |
| `sin()`   | `sin()`   | `csin()`   |
| `tan()`   | `tan()`   | `ctan()`   |
| `cosh()`  | `cosh()`  | `ccosh()`  |
| `sinh()`  | `sinh()`  | `csinh()`  |
| `tanh()`  | `tanh()`  | `ctanh()`  |
| `exp()`   | `exp()`   | `cexp()`   |
| `log()`   | `log()`   | `clog()`   |
| `pow()`   | `pow()`   | `cpow()`   |
| `sqrt()`  | `sqrt()`  | `csqrt()`  |
| `fabs()`  | `fabs()`  | `cabs()`   |

以下宏不存在复数函数，因此将复数值传递给通用参数会调用未定义行为：

| `atan2()`    | `fma()`    | `llround()`    | `remainder()` |
| ------------ | ---------- | -------------- | ------------- |
| `cbrt()`     | `fmax()`   | `log10()`      | `remquo()`    |
| `ceil()`     | `fmin()`   | `log1p()`      | `rint()`      |
| `copysign()` | `fmod()`   | `log2()`       | `round()`     |
| `erf()`      | `frexp()`  | `logb()`       | `scalbn()`    |
| `erfc()`     | `hypot()`  | `lrint()`      | `scalbln()`   |
| `exp2()`     | `ilogb()`  | `lround()`     | `tgamma()`    |
| `expm1()`    | `ldexp()`  | `nearbyint()`  | `trunc()`     |
| `fdim()`     | `lgamma()` | `nextafter()`  |               |
| `floor()`    | `llrint()` | `nexttoward()` |               |

以下宏始终展开为复数函数：

| `carg()` | `cimag()` | `conj()` | `cproj()` | `creal()` |
| -------- | --------- | -------- | --------- | --------- |

此头文件包含

```c
#include <complex.h>
```

和

```c
#include <math.h>
```

## 标准

头文件

```c
#include <tgmath.h>
```

遵循 ISO/IEC 9899:1999 ("ISO C99") 标准。

## 历史

头文件

```c
#include <tgmath.h>
```

首次出现于 FreeBSD 5.3。

## 编译器支持

在 ISO/IEC 9899:2011 ("ISO C11") 之前，头文件

```c
#include <tgmath.h>
```

无法用严格符合标准的 C 代码实现，需要特殊的编译器支持。从 ISO/IEC 9899:2011 ("ISO C11") 开始，此头文件可以使用 `_Generic` 语言关键字实现。除了支持此关键字的编译器外，此头文件还可以在 GCC 上工作。

## 缺陷

此处提到的许多函数未在

```c
#include <math.h>
```

或

```c
#include <complex.h>
```

中提供原型，因为它们尚未实现。这阻止了相应的类型通用宏正常工作。


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