C标准函数库的历史沿革

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>包含断言宏，被用来在程序的调试版本中帮助检测逻辑错误以及其他类型的bug。 <complex.h> C99 一组操作复数的函数。 <ctype.h>定义了一组函数，用来根据类型来给字符分类，或者进行大小写转换，而不关心所使用的字符集（通常是ASCII或其扩展字符集，也有EBCDIC）。 <errno.h>用来测试由库函数报的错误代码。 <fenv.h> C99 定义了一组用来控制浮点数环境的函数。 <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 theinteger types. <locale.h>定义C语言本地化函数. <math.h>定义C语言数学函数。 <setjmp.h>定义了宏setjmp和longjmp，在非局部跳转的时候使用。 <signal.h>定义C语言信号处理函数。 <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>定义C语言字符串处理函数 <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