stdlib.h标准库头.doc

stdlib.h 标准库头文件一、 简介stdlib 头文件即standard library标准库头文件 stdlib 头文件里包含了C、C+语言的最常用的系统函数 该文件包含了的C语言标准库函数的定义 stdlib.h里面定义了五种类型、一些宏和通用工具函数。 类型例如size_t、wchar_t、div_t、ldiv_t和lldiv_t； 宏例如EXIT_FAILURE、EXIT_SUCCESS、RAND_MAX和MB_CUR_MAX等等； 常用的函数如malloc()、calloc()、realloc()、free()、system()、atoi()、atol()、rand()、srand()、exit()等等。二、 Stdlib.H具体内容/*stdlib.h - declarations/definitions for commonly used library functions* Copyright (c) 1985-1997, Microsoft Corporation. All rights reserved.*Purpose:* This include file contains the function declarations for commonly* used library functions which either dont fit somewhere else, or,* cannot be declared in the normal place for other reasons.* ANSI* Public*/#if _MSC_VER 1000#pragma once#endif /* _MSC_VER 1000 */#ifndef _INC_STDLIB#define _INC_STDLIB#if !defined (_WIN32) & !defined (_MAC)#error ERROR: Only Mac or Win32 targets supported!#endif /* !defined (_WIN32) & !defined (_MAC) */#ifndef _CRTBLD/* This version of the header files is NOT for user programs. * It is intended for use when building the C runtimes ONLY. * The version intended for public use will not have this message. */#error ERROR: Use of C runtime library internal header file.#endif /* _CRTBLD */#ifdef _MSC_VER/* * Currently, all MS C compilers for Win32 platforms default to 8 byte * alignment. */#pragma pack(push,8)#endif /* _MSC_VER */#ifdef _cplusplusextern C #endif /* _cplusplus */#ifndef _INTERNAL_IFSTRIP_#include #endif /* _INTERNAL_IFSTRIP_ */* Define _CRTIMP */#ifndef _CRTIMP#ifdef CRTDLL#define _CRTIMP _declspec(dllexport)#else /* CRTDLL */#ifdef _DLL#define _CRTIMP _declspec(dllimport)#else /* _DLL */#define _CRTIMP#endif /* _DLL */#endif /* CRTDLL */#endif /* _CRTIMP */* Define _cdecl for non-Microsoft compilers */#if (!defined (_MSC_VER) & !defined (_cdecl)#define _cdecl#endif /* (!defined (_MSC_VER) & !defined (_cdecl) */* Define _CRTAPI1 (for compatibility with the NT SDK) */#ifndef _CRTAPI1#if _MSC_VER = 800 & _M_IX86 = 300#define _CRTAPI1 _cdecl#else /* _MSC_VER = 800 & _M_IX86 = 300 */#define _CRTAPI1#endif /* _MSC_VER = 800 & _M_IX86 = 300 */#endif /* _CRTAPI1 */#ifndef _SIZE_T_DEFINEDtypedef unsigned int size_t;#define _SIZE_T_DEFINED#endif /* _SIZE_T_DEFINED */#ifndef _WCHAR_T_DEFINEDtypedef unsigned short wchar_t;#define _WCHAR_T_DEFINED#endif /* _WCHAR_T_DEFINED */* Define NULL pointer value */#ifndef NULL#ifdef _cplusplus#define NULL 0#else /* _cplusplus */#define NULL (void *)0)#endif /* _cplusplus */#endif /* NULL */* Definition of the argument values for the exit() function */#define EXIT_SUCCESS 0#define EXIT_FAILURE 1#ifndef _ONEXIT_T_DEFINEDtypedef int (_cdecl * _onexit_t)(void);#if !_STDC_/* Non-ANSI name for compatibility */#define onexit_t _onexit_t#endif /* !_STDC_ */#define _ONEXIT_T_DEFINED#endif /* _ONEXIT_T_DEFINED */* Data structure definitions for div and ldiv runtimes. */#ifndef _DIV_T_DEFINEDtypedef struct _div_t int quot; int rem; div_t;typedef struct _ldiv_t long quot; long rem; ldiv_t;#define _DIV_T_DEFINED#endif /* _DIV_T_DEFINED */* Maximum value that can be returned by the rand function. */#define RAND_MAX 0x7fff/* * Maximum number of bytes in multi-byte character in the current locale * (also defined in ctype.h). */#ifndef MB_CUR_MAX#ifndef _INTERNAL_IFSTRIP_#if defined (_DLL) & defined (_M_IX86)/* Retained for compatibility with VC+ 5.0 and earlier versions */_CRTIMP int * _cdecl _p_mb_cur_max(void);#endif /* defined (_DLL) & defined (_M_IX86) */#endif /* _INTERNAL_IFSTRIP_ */#define MB_CUR_MAX _mb_cur_max_CRTIMP extern int _mb_cur_max;#endif /* MB_CUR_MAX */* Minimum and maximum macros */#define _max(a,b) (a) (b) ? (a) : (b)#define _min(a,b) (a) = 1200_CRTIMP _declspec(noreturn) void _cdecl abort(void);_CRTIMP _declspec(noreturn) void _cdecl exit(int);#else /* _MSC_VER = 1200 */_CRTIMP void _cdecl abort(void);_CRTIMP void _cdecl exit(int);#endif /* _MSC_VER = 1200 */#if defined (_M_MRX000)_CRTIMP int _cdecl abs(int);#else /* defined (_M_MRX000) */ int _cdecl abs(int);#endif /* defined (_M_MRX000) */ int _cdecl atexit(void (_cdecl *)(void);_CRTIMP double _cdecl atof(const char *);_CRTIMP int _cdecl atoi(const char *);_CRTIMP long _cdecl atol(const char *);#ifdef _M_M68K_CRTIMP long double _cdecl _atold(const char *);#endif /* _M_M68K */_CRTIMP void * _cdecl bsearch(const void *, const void *, size_t, size_t, int (_cdecl *)(const void *, const void *);_CRTIMP void * _cdecl calloc(size_t, size_t);_CRTIMP div_t _cdecl div(int, int);_CRTIMP void _cdecl free(void *);_CRTIMP char * _cdecl getenv(const char *);_CRTIMP char * _cdecl _itoa(int, char *, int);#if _INTEGRAL_MAX_BITS = 64 _CRTIMP char * _cdecl _i64toa(_int64, char *, int);_CRTIMP char * _cdecl _ui64toa(unsigned _int64, char *, int);_CRTIMP _int64 _cdecl _atoi64(const char *);#endif /* _INTEGRAL_MAX_BITS = 64 */#if defined (_M_MRX000)_CRTIMP long _cdecl labs(long);#else /* defined (_M_MRX000) */ long _cdecl labs(long);#endif /* defined (_M_MRX000) */_CRTIMP ldiv_t _cdecl ldiv(long, long);_CRTIMP char * _cdecl _ltoa(long, char *, int);_CRTIMP void * _cdecl malloc(size_t);_CRTIMP int _cdecl mblen(const char *, size_t);_CRTIMP size_t _cdecl _mbstrlen(const char *s);_CRTIMP int _cdecl mbtowc(wchar_t *, const char *, size_t);_CRTIMP size_t _cdecl mbstowcs(wchar_t *, const char *, size_t);_CRTIMP void _cdecl qsort(void *, size_t, size_t, int (_cdecl *) (const void *, const void *);_CRTIMP int _cdecl rand(void);_CRTIMP void * _cdecl realloc(void *, size_t);_CRTIMP int _cdecl _set_error_mode(int);_CRTIMP void _cdecl srand(unsigned int);_CRTIMP double _cdecl strtod(const char *, char *);_CRTIMP long _cdecl strtol(const char *, char *, int);#ifdef _M_M68K_CRTIMP long double _cdecl _strtold(const char *, char *);#endif /* _M_M68K */_CRTIMP unsigned long _cdecl strtoul(const char *, char *, int);#ifndef _MAC_CRTIMP int _cdecl system(const char *);#endif /* _MAC */_CRTIMP char * _cdecl _ultoa(unsigned long, char *, int);_CRTIMP int _cdecl wctomb(char *, wchar_t);_CRTIMP size_t _cdecl wcstombs(char *, const wchar_t *, size_t);#ifndef _MAC#ifndef _WSTDLIB_DEFINED/* wide function prototypes, also declared in wchar.h */_CRTIMP wchar_t * _cdecl _itow (int, wchar_t *, int);_CRTIMP wchar_t * _cdecl _ltow (long, wchar_t *, int);_CRTIMP wchar_t * _cdecl _ultow (unsigned long, wchar_t *, int);_CRTIMP double _cdecl wcstod(const wchar_t *, wchar_t *);_CRTIMP long _cdecl wcstol(const wchar_t *, wchar_t *, int);_CRTIMP unsigned long _cdecl wcstoul(const wchar_t *, wchar_t *, int);_CRTIMP wchar_t * _cdecl _wgetenv(const wchar_t *);_CRTIMP int _cdecl _wsystem(const wchar_t *);_CRTIMP int _cdecl _wtoi(const wchar_t *);_CRTIMP long _cdecl _wtol(const wchar_t *);#if _INTEGRAL_MAX_BITS = 64 _CRTIMP wchar_t * _cdecl _i64tow(_int64, wchar_t *, int);_CRTIMP wchar_t * _cdecl _ui64tow(unsigned _int64, wchar_t *, int);_CRTIMP _int64 _cdecl _wtoi64(const wchar_t *);#endif /* _INTEGRAL_MAX_BITS = 64 */#define _WSTDLIB_DEFINED#endif /* _WSTDLIB_DEFINED */#endif /* _MAC */_CRTIMP char * _cdecl _ecvt(double, int, int *, int *);#if _MSC_VER = 1200_CRTIMP _declspec(noreturn) void _cdecl _exit(int);#else /* _MSC_VER = 1200 */_CRTIMP void _cdecl _exit(int);#endif /* _MSC_VER = 1200 */_CRTIMP char * _cdecl _fcvt(double, int, int *, int *);_CRTIMP char * _cdecl _fullpath(char *, const char *, size_t);_CRTIMP char * _cdecl _gcvt(double, int, char *); unsigned long _cdecl _lrotl(unsigned long, int); unsigned long _cdecl _lrotr(unsigned long, int);#ifndef _MAC_CRTIMP void _cdecl _makepath(char *, const char *, const char *, const char *, const char *);#endif /* _MAC */ _onexit_t _cdecl _onexit(_onexit_t);_CRTIMP void _cdecl perror(const char *);_CRTIMP int _cdecl _putenv(const char *); unsigned int _cdecl _rotl(unsigned int, int); unsigned int _cdecl _rotr(unsigned int, int);_CRTIMP void _cdecl _searchenv(const char *, const char *, char *);#ifndef _MAC_CRTIMP void _cdecl _splitpath(const char *, char *, char *, char *, char *);#endif /* _MAC */_CRTIMP void _cdecl _swab(char *, char *, int);#ifndef _MAC#ifndef _WSTDLIBP_DEFINED/* wide function prototypes, also declared in wchar.h */_CRTIMP wchar_t * _cdecl _wfullpath(wchar_t *, const wchar_t *, size_t);_CRTIMP void _cdecl _wmakepath(wchar_t *, const wchar_t *, const wchar_t *, const wchar_t *, const wchar_t *);_CRTIMP void _cdecl _wperror(const wchar_t *);_CRTIMP int _cdecl _wputenv(const wchar_t *);_CRTIMP void _cdecl _wsearchenv(const wchar_t *, const wchar_t *, wchar_t *);_CRTIMP void _cdecl _wsplitpath(const wchar_t *, wchar_t *, wchar_t *, wchar_t *, wchar_t *);#define _WSTDLIBP_DEFINED#endif /* _WSTDLIBP_DEFINED */#endif /* _MAC */* - The following functions are OBSOLETE - */* The Win32 API SetErrorMode, Beep and Sleep should be used instead. */#ifndef _MAC_CRTIMP void _cdecl _seterrormode(int);_CRTIMP void _cdecl _beep(unsigned, unsigned);_CRTIMP void _cdecl _sleep(unsigned long);#endif /* _MAC */* - The preceding functions are OBSOLETE - */#if !_STDC_/* - The declarations below should not be in stdlib.h - */* - and will be removed in a future release. Include - */* - ctype.h to obtain these declarations. - */#ifndef tolower_CRTIMP int _cdecl tolower(int);#endif /* tolower */#ifndef toupper_CRTIMP int _cdecl toupper(int);#endif /* toupper */* - The declarations above will be removed. - */#endif /* !_STDC_ */#ifdef _MTchar * _cdecl _getenv_lk(const char *); /* _MTHREAD_ONLY */#ifndef _MACwchar_t * _cdecl _wgetenv_lk(const wchar_t *); /* _MTHREAD_ONLY */#endif /* _MAC */int _cdecl _putenv_lk(const char *); /* _MTHREAD_ONLY */#ifndef _MACint _cdecl _wputenv_lk(const wchar_t *); /* _MTHREAD_ONLY */#endif /* _MAC */int _cdecl _mblen_lk(const char *, size_t); /* _MTHREAD_ONLY */int _cdecl _mbtowc_lk(wchar_t*,const char*,size_t); /* _MTHREAD_ONLY */size_t _cdecl _mbstowcs_lk(wchar_t*,const char*,size_t); /* _MTHREAD_ONLY */int _cdecl _wctomb_lk(char*,wchar_t); /* _MTHREAD_ONLY */size_t _cdecl _wcstombs_lk(char*,const wchar_t*,size_t); /* _MTHREAD_ONLY */#else /* _MT */#define _getenv_lk(envvar) getenv(envvar) /* _MTHREAD_ONLY */#ifndef _MAC#define _wgetenv_lk(envvar) _wgetenv(envvar) /* _MTHREAD_ONLY */#endif /* _MAC */#define _putenv_lk(envvar) _putenv(envvar) /* _MTHREAD_ONLY */#ifndef _MAC#define _wputenv_lk(envvar) _wputenv(envvar) /* _MTHREAD_ONLY */#endif /* _MAC */#define _mblen_lk(s,n) mblen(s,n) /* _MTHREAD_ONLY */#define _mbtowc_lk(pwc,s,n) mbtowc(pwc,s,n) /* _MTHREAD_ONLY */#define _mbstowcs_lk(pwcs,s,n) mbstowcs(pwcs,s,n) /* _MTHREAD_ONLY */#define _wctomb_lk(s,wchar) wctomb(s,wchar) /* _MTHREAD_ONLY */#define _wcstombs_lk(s,pwcs,n) wcstombs(s,pwcs,n) /* _MTHREAD_ONLY */#endif /* _MT */#if !_STDC_/* Non-ANSI names for compatibility */#ifndef _cplusplus#define max(a,b) (a) (b) ? (a) : (b)#define min(a,b) (a) (b) ? (a) : (b)#endif /* _cplusplus */#define sys_errlist _sys_errlist#define sys_nerr _sys_nerr#define environ _environ_CRTIMP char * _cdecl ecvt(double, int, int *, int *);_CRTIMP char * _cdecl fcvt(double, int, int *, int *);_CRTIMP char * _cdecl gcvt(double, int, char *);_CRTIMP char * _cdecl itoa(int, char *, int);_CRTIMP char * _cdecl ltoa(long, char *, int); onexit_t _cdecl onexit(onexit_t);_CRTIMP int _cdecl putenv(const char *);_CRTIMP void _cdecl swab(char *, char *, int);_CRTIMP char * _cdecl ultoa(unsigned long, char *, int);#endif /* !_STDC_ */#ifdef _cplusplus#endif /* _cplusplus */#ifdef _MSC_VER#pragma pack(pop)#endif /* _MSC_VER */#endif /* _INC_STDLIB */三、 stdlib.h用法1函数名称: calloc 函数原型: void * calloc(unsigned n,unsign size); 函数功能: 分配n个数据项的内存连续空间,每个数据项的大小为size 函数返回: 分配内存单元的起始地址,如果不成功,返回0 2函数名称: free 函数原型: void free(void* p); 函数功能: 释放p所指的内存区 函数返回: 参数说明: p-被释放的指针 3函数名称: malloc 函数原