在
C语言程序设计里，C 标准函数库（C Standard library）收集所有目前符合标准的头文件（head file），以及常用的函数库实现程序，例如
I/O 输入输出和字符串控制。不像
COBOL、Fortran 和
PL/I等编程语言，在 C 语言的工作任务里不会包含嵌入的关键字，所以几乎所有的 C 语言程序都是由标准函数库的函数来创建的。
目录 |
设计
每一个函数的名称与特性会被写成一个电脑文件，这个文件就称为头文件，但是实际的函数实现是被分存到函数库文件里。头文件的命名和领域是很常见的，但是函数库的组织架构也会因为不同的编译器而有所不同。标准函数库通常会随附在编译器上。因为
C 编译器常会提供一些额外的非 ANSI C 函数功能，所以某个随附在特定编译器上的标准函数库，对其他不同的编译器来说，是不兼容的。
设计品质
大多 C 标准函数库在设计上做得相当不错。有些少部分的，会为了商业优势和利益，会把某些旧函数视同错误或提出警告。字符串输入函数 gets()（以及
scanf() 读取字符串输入的使用上）是很多缓存溢出的原因，而且大多的程序设计指南会建议避免使用它。另一个较为奇特的函数是
strtok()，它原本是作为早期的词汇分析用途，但是它非常容易出错（fragile），而且很难使用。
历史沿革
1995年，Normative Addendum 1 (NA1)批准了三个头文件(iso646.h, wchar.h, and wctype.h)增加到C标准函数库中。C99标准增加了六个头文件(complex.h, fenv.h, inttypes.h, stdbool.h, stdint.h, and tgmath.h)。C11标准中又新增了5个头文件(stdalign.h,
stdatomic.h, stdnoreturn.h, threads.h, and uchar.h)。至此，C标准函数库共29个头文件：
| 名字 | 源自 | 描述 |
|---|---|---|
<assert.h> |
Contains the assert macro, used to assist with detecting logical errors and other types of bug in debugging versions of a program. | |
<complex.h> |
C99 | A set of functions for manipulating 复数. |
<ctype.h> |
Defines set of functions used to classify characters by their types or to convert between upper and lower case in a way that is independent of the used character set (typically ASCII or one of its extensions, although implementations utilizing EBCDIC are also known). |
|
<errno.h> |
For testing error codes reported by library functions. | |
<fenv.h> |
C99 | Defines a set of functions for controlling 浮点数 environment. |
<float.h> |
Defines macro constants specifying the implementation-specific properties of the 浮点数 library. |
|
<inttypes.h> |
C99 | Defines exact width integer types. |
<iso646.h> |
NA1 | Defines several macros that are equivalent to some of the operators in C. For programming in ISO 646 variant character sets. |
<limits.h> |
Defines macro constants specifying the implementation-specific properties of the integer types. | |
<locale.h> |
Defines C localization functions. | |
<math.h> |
Defines C mathematical functions. | |
<setjmp.h> |
Declares the macros setjmp and longjmp, which are used for non-local exits. |
|
<signal.h> |
Defines C signal handling functions. | |
<stdalign.h> |
C11 | For querying and specifying the data structure alignment of objects. |
<stdarg.h> |
For accessing a varying number of arguments passed to functions. | |
<stdatomic.h> |
C11 | For atomic operations on data shared between threads. |
<stdbool.h> |
C99 | Defines a boolean data type. |
<stddef.h> |
Defines several useful types and macros. | |
<stdint.h> |
C99 | Defines exact width integer types. |
<stdio.h> |
Defines core input and output functions | |
<stdlib.h> |
Defines numeric conversion functions, pseudo-random numbers generation functions, dynamicmemory allocation, process control functions | |
<stdnoreturn.h> |
C11 | For specifying non-returning functions. |
<string.h> |
Defines C string handling functions. | |
<tgmath.h> |
C99 | Defines type-generic mathematical functions. |
<threads.h> |
C11 | Defines functions for managing multiple threads as well as mutexes and condition variables. |
<time.h> |
Defines date and time handling functions | |
<uchar.h> |
C11 | Types and functions for manipulating Unicode characters. |
<wchar.h> |
NA1 | Defines wide string handling functions. |
<wctype.h> |
NA1 | Defines set of functions used to classify wide characters by their types or to convert between upper and lower case |
参考资料
其他项目
外部链接
- The C Standard Library：A detailed description of the header files
- The C Library Reference Guide
- Microsoft
C Run-Time Libraries on MSDN - [Coding Programmer Page / Library Reference and Examples] (englisch)
| 隐藏▲ | |
|---|---|
| 函数库 | |
| 特性 | |
| 延伸的相关编程语言 | |
| C 与其他的编程语言 | |
| 编译器 |
Borland Turbo C ·
Clang · GCC · LCC · Pelles C · PCC · TCC · Visual C++ · C++/CLI · C++/CX · Watcom C/C++ compiler |