stdio.h c头文件

       一般会把用来#include的文件的扩展名叫 .h，称其为头文件。 #include文件的目的就是把多个编译单元（也就是c或者cpp文件）公用的内容，单独放在一个文件里减少整体代码尺寸；或者提供跨工程公共代码。

stdio 就是指 “standard input & output"（标准输入输出）所以，源代码中如用到标准输入输出函数时，就要包含这个头文件！

标准函数：

int getchar() //从标准输入设备读入一个字符int putchar() //向标准输出设备写出一个字符int scanf(char *format[,argument…]) //从标准输入设备读入格式化后的数据int printf(char *format[,argument…]) //向标准输出设备输出格式化字符串char *gets(char *string) //从标准输入设备读入一个字符串int puts(char *string) //向标准输出设备输出一个字符串int sprintf(char*string,char*format[,…]) //把格式化的数据写入某个字符串缓冲区

文件说明：

/** stdio.h* This file has no copyright assigned and is placed in the Public Domain.* This file is a part of the mingw-runtime package.* No warranty is given; refer to the file DISCLAIMER within the package.** Definitions of types and prototypes of functions for standard input and* output.** NOTE: The file manipulation functions provided by Microsoft seem to* work with either slash (/) or backslash (\) as the directory separator.**/

宏定义：

#ifndef _STDIO_H_#define _STDIO_H_/* All the headers include this file. */#include <_mingw.h>#ifndef RC_INVOKED#define __need_size_t#define __need_NULL#define __need_wchar_t#define __need_wint_t#include <stddef.h>#define __need___va_list#include <stdarg.h>#endif /* Not RC_INVOKED *//* Flags for the iobuf structure */#define _IOREAD 1 /* currently reading */#define _IOWRT 2 /* currently writing */#define _IORW 0x0080 /* opened as "r+w" *//** The three standard file pointers provided by the run time library.* NOTE: These will go to the bit-bucket silently in GUI applications!*/#define STDIN_FILENO 0#define STDOUT_FILENO 1#define STDERR_FILENO 2/* Returned by various functions on end of file condition or error. */#define EOF (-1)/** The maximum length of a file name. You should useGetVolumeInformation* instead of this constant. But hey, this works.* Also defined in io.h.*/#ifndef FILENAME_MAX#define FILENAME_MAX (260)#endif/** The maximum number of files that may be open at once. I have set this to* a conservative number. The actual value may be higher.*/#define FOPEN_MAX (20)/* After creating this many names,tmpnamand tmpfile return NULL */#defineTMP_MAX 32767/** Tmpnam, tmpfile and, sometimes, _tempnamtry to create* temp files in the root directory of the current drive* (not in pwd, as suggested by some older MS doc's).* Redefining these macros does not effect the CRT functions.*/#define _P_tmpdir "\\"#ifndef __STRICT_ANSI__#define P_tmpdir _P_tmpdir#endif#define _wP_tmpdir L"\\"/** The maximum size of name (including NUL) that will be put in the user* supplied buffer caName fortmpnam.* Inferred from the size of the static buffer returned by tmpnam* when passed a NULL argument. May actually be smaller.*/#define L_tmpnam (16)#define _IOFBF 0x0000 /* full buffered */#define _IOLBF 0x0040 /* line buffered */#define _IONBF 0x0004 /* not buffered */#define _IOMYBUF 0x0008 /* stdio malloc()'d buffer */#define _IOEOF 0x0010 /* EOF reached on read */#define_IOERR 0x0020 /* I/O error from system */#define_IOSTRG 0x0040 /* Strange or no file descriptor */#ifdef _POSIX_SOURCE# define _IOAPPEND 0x0200#endif/** The buffer size as used bysetbufsuch that it is equivalent to* (void) setvbuf(fileSetBuffer, caBuffer, _IOFBF, BUFSIZ).*/#define BUFSIZ 512/* Constants for nOrigin indicating the position relative to which fseek* sets the file position. Enclosed in ifdefs because io.h could also* define them. (Though not anymore since io.h includes this file now.) */#ifndef SEEK_SET#define SEEK_SET (0)#endif#ifndef SEEK_CUR#define SEEK_CUR (1)#endif#ifndef SEEK_END#define SEEK_END (2)#endif#ifndef RC_INVOKED#ifndef __VALIST#ifdef __GNUC__#define __VALIST __gnuc_va_list#else#define __VALIST char*#endif#endif /* defined __VALIST *//** The structure underlying the FILE type.** Some believe that nobody in their right mind should make use of the* internals of this structure. Provided by Pedro A. Aranda Gutiirrez*/#ifndef _FILE_DEFINED#define _FILE_DEFINED

结构体定义：

typedef struct _iobuf{char* _ptr;int _cnt;char* _base;int _flag;int _file;int _charbuf;int _bufsiz;char* _tmpfname;} FILE;#endif /* Not _FILE_DEFINED *//** The standard file handles*/#ifndef __DECLSPEC_SUPPORTEDextern FILE (*_imp___iob)[]; /* A pointer to an array of FILE */#define _iob (*_imp___iob) /* An array of FILE */#else /* __DECLSPEC_SUPPORTED */__MINGW_IMPORT FILE _iob[]; /* An array of FILE imported from DLL. */#endif /* __DECLSPEC_SUPPORTED */#define stdin (&_iob[STDIN_FILENO])#define stdout (&_iob[STDOUT_FILENO])#define stderr (&_iob[STDERR_FILENO])

操作函数定义：

#ifdef __cplusplusextern "C" {#endif/** File Operations*/_CRTIMP FILE* __cdecl fopen (const char*, const char*);_CRTIMP FILE* __cdecl freopen (const char*, const char*, FILE*);_CRTIMP int __cdecl fflush (FILE*);_CRTIMP int __cdecl fclose (FILE*);/* MS puts remove & rename (but not wide versions) in io.h also */_CRTIMP int __cdecl remove (const char*);_CRTIMP int __cdecl rename (const char*, const char*);_CRTIMP FILE* __cdecl tmpfile (void);_CRTIMP char* __cdecltmpnam(char*);#ifndef __STRICT_ANSI___CRTIMP char* __cdecl _tempnam(const char*, const char*);_CRTIMP int __cdecl _rmtmp(void);#ifndef NO_OLDNAMES_CRTIMP char* __cdecltempnam(const char*, const char*);_CRTIMP int __cdecl rmtmp(void);#endif#endif /* __STRICT_ANSI__ */_CRTIMP int __cdecl setvbuf (FILE*, char*, int,size_t);_CRTIMP void __cdeclsetbuf(FILE*, char*);/** Formatted Output*/_CRTIMP int __cdecl fprintf (FILE*, const char*, ...);_CRTIMP int __cdecl printf (const char*, ...);_CRTIMP int __cdecl sprintf (char*, const char*, ...);_CRTIMP int __cdecl _snprintf (char*,size_t, const char*, ...);_CRTIMP int __cdecl vfprintf (FILE*, const char*, __VALIST);_CRTIMP int __cdecl vprintf (const char*, __VALIST);_CRTIMP int __cdecl vsprintf (char*, const char*, __VALIST);_CRTIMP int __cdecl _vsnprintf (char*,size_t, const char*, __VALIST);#ifndef __NO_ISOCEXT /* externs in libmingwex.a */int __cdecl snprintf(char* s,size_tn, const char* format, ...);__CRT_INLINE int __cdeclvsnprintf (char* s,size_tn, const char* format, __VALIST arg){ return _vsnprintf ( s, n, format, arg); }int __cdeclvscanf(const char * __restrict__, __VALIST);int __cdeclvfscanf(FILE * __restrict__, const char * __restrict__,__VALIST);int __cdeclvsscanf(const char * __restrict__,const char * __restrict__, __VALIST);#endif/** Formatted Input*/_CRTIMP int __cdecl fscanf (FILE*, const char*, ...);_CRTIMP int __cdecl scanf (const char*, ...);_CRTIMP int __cdecl sscanf (const char*, const char*, ...);/** Character Input and Output Functions*/_CRTIMP int __cdecl fgetc (FILE*);_CRTIMP char* __cdecl fgets (char*, int, FILE*);_CRTIMP int __cdecl fputc (int, FILE*);_CRTIMP int __cdecl fputs (const char*, FILE*);_CRTIMP char* __cdecl gets (char*);_CRTIMP int __cdecl puts (const char*);_CRTIMP int __cdeclungetc(int, FILE*);/* Traditionally, getc and putc are defined as macros. but thestandard doesn't say that they must be macros.We use inline functions here to allow the fast versionsto be used in C++ with namespace qualification, eg., ::getc._filbuf and _flsbuf are not thread-safe. */_CRTIMP int __cdecl _filbuf (FILE*);_CRTIMP int __cdecl _flsbuf (int, FILE*);#if !defined _MT__CRT_INLINE int __cdecl getc (FILE* __F){return (--__F->_cnt >= 0)? (int) (unsigned char) *__F->_ptr++: _filbuf (__F);}__CRT_INLINE int __cdecl putc (int __c, FILE* __F){return (--__F->_cnt >= 0)? (int) (unsigned char) (*__F->_ptr++ = (char)__c): _flsbuf (__c, __F);}__CRT_INLINE int __cdecl getchar (void){return (--stdin->_cnt >= 0)? (int) (unsigned char) *stdin->_ptr++: _filbuf (stdin);}__CRT_INLINE int __cdecl putchar(int __c){return (--stdout->_cnt >= 0)? (int) (unsigned char) (*stdout->_ptr++ = (char)__c): _flsbuf (__c, stdout);}#else /* Use library functions. */_CRTIMP int __cdecl getc (FILE*);_CRTIMP int __cdecl putc (int, FILE*);_CRTIMP int __cdecl getchar (void);_CRTIMP int __cdecl putchar (int);#endif/** Direct Input and Output Functions*/_CRTIMPsize_t__cdecl fread (void*,size_t,size_t, FILE*);_CRTIMPsize_t__cdecl fwrite (const void*,size_t, size_t, FILE*);/** File Positioning Functions*/_CRTIMP int __cdecl fseek (FILE*, long, int);_CRTIMP long __cdecl ftell (FILE*);_CRTIMP void __cdecl rewind (FILE*);#ifdef __USE_MINGW_FSEEK /* These are in libmingwex.a *//** Workaround for limitations on win9x where a file contents are* not zero'd out if you seek past the end and then write.*/int __cdecl __mingw_fseek (FILE *, long, int);int __cdecl __mingw_fwrite (const void*, size_t, size_t, FILE*);#define fseek(fp, offset, whence) __mingw_fseek(fp, offset, whence)#define fwrite(buffer, size, count, fp) __mingw_fwrite(buffer, size, count, fp)#endif /* __USE_MINGW_FSEEK *//** An opaque data type used for storing file positions... The contents of* this type are unknown, but we (the compiler) need to know the size* because the programmer usingfgetposandfsetposwill be setting aside* storage for fpos_t structres. Actually I tested using a byte array and* it is fairly evident that the fpos_t type is a long (in CRTDLL.DLL).* Perhaps an unsigned long? TODO? It's definitely a 64-bit number in* MSVCRT however, and for now `long long' will do.*/#ifdef __MSVCRT__typedef long long fpos_t;#elsetypedef long fpos_t;#endif_CRTIMP int __cdeclfgetpos(FILE*, fpos_t*);_CRTIMP int __cdeclfsetpos(FILE*, const fpos_t*);/** Error Functions*/_CRTIMP int __cdecl feof (FILE*);_CRTIMP int __cdecl ferror (FILE*);#ifdef __cplusplusinline int __cdecl feof (FILE* __F){ return __F->_flag & _IOEOF; }inline int __cdecl ferror (FILE* __F){ return __F->_flag & _IOERR; }#else#define feof(__F) ((__F)->_flag & _IOEOF)#define ferror(__F) ((__F)->_flag & _IOERR)#endif_CRTIMP void __cdeclclearerr(FILE*);_CRTIMP void __cdecl perror (const char*);#ifndef __STRICT_ANSI__/** Pipes*/_CRTIMP FILE* __cdecl _popen (const char*, const char*);_CRTIMP int __cdecl _pclose (FILE*);#ifndef NO_OLDNAMES_CRTIMP FILE* __cdecl popen (const char*, const char*);_CRTIMP int __cdecl pclose (FILE*);#endif/** Other Non ANSI functions*/_CRTIMP int __cdecl _flushall (void);_CRTIMP int __cdecl _fgetchar(void);_CRTIMP int __cdecl _fputchar(int);_CRTIMP FILE* __cdecl _fdopen(int, const char*);_CRTIMP int __cdecl _fileno (FILE*);_CRTIMP int __cdecl _fcloseall(void);_CRTIMP FILE* __cdecl _fsopen(const char*, const char*, int);#ifdef __MSVCRT___CRTIMP int __cdecl _getmaxstdio(void);_CRTIMP int __cdecl _setmaxstdio(int);#endif#ifndef _NO_OLDNAMES_CRTIMP int __cdeclfgetchar(void);_CRTIMP int __cdeclfputchar(int);_CRTIMP FILE* __cdeclfdopen(int, const char*);_CRTIMP int __cdecl fileno (FILE*);#endif /* Not _NO_OLDNAMES */#define _fileno(__F) ((__F)->_file)#ifndef _NO_OLDNAMES#define fileno(__F) ((__F)->_file)#endif#if defined (__MSVCRT__) && !defined (__NO_MINGW_LFS)#include <sys/types.h>__CRT_INLINE FILE* __cdecl fopen64 (const char* filename, const char* mode){return fopen (filename, mode);}int __cdecl fseeko64 (FILE*, off64_t, int);#ifdef __USE_MINGW_FSEEKint __cdecl __mingw_fseeko64 (FILE *, off64_t, int);#define fseeko64(fp, offset, whence) __mingw_fseeko64(fp, offset, whence)#endif__CRT_INLINE off64_t __cdecl ftello64 (FILE * stream){fpos_t pos;if (fgetpos(stream, &pos))return -1LL;elsereturn ((off64_t) pos);}#endif /* __NO_MINGW_LFS */#endif /* Not __STRICT_ANSI__ *//* Wide versions */#ifndef _WSTDIO_DEFINED/* also in wchar.h - keep in sync */_CRTIMP int __cdecl fwprintf (FILE*, constwchar_t*, ...);_CRTIMP int __cdecl wprintf (constwchar_t*, ...);_CRTIMP int __cdeclswprintf(wchar_t*, constwchar_t*, ...);_CRTIMP int __cdecl _snwprintf (wchar_t*,size_t, constwchar_t*, ...);_CRTIMP int __cdecl vfwprintf (FILE*, constwchar_t*, __VALIST);_CRTIMP int __cdecl vwprintf (constwchar_t*, __VALIST);_CRTIMP int __cdecl vswprintf (wchar_t*, const wchar_t*, __VALIST);_CRTIMP int __cdecl _vsnwprintf (wchar_t*,size_t, const wchar_t*, __VALIST);_CRTIMP int __cdecl fwscanf (FILE*, constwchar_t*, ...);_CRTIMP int __cdecl wscanf (const wchar_t*, ...);_CRTIMP int __cdecl swscanf (constwchar_t*, const wchar_t*, ...);_CRTIMP wint_t __cdecl fgetwc (FILE*);_CRTIMP wint_t __cdecl fputwc (wchar_t, FILE*);_CRTIMP wint_t __cdecl ungetwc (wchar_t, FILE*);#ifdef __MSVCRT___CRTIMPwchar_t* __cdecl fgetws (wchar_t*, int, FILE*);_CRTIMP int __cdecl fputws (constwchar_t*, FILE*);_CRTIMP wint_t __cdecl getwc (FILE*);_CRTIMP wint_t __cdecl getwchar (void);_CRTIMPwchar_t* __cdecl _getws (wchar_t*);_CRTIMP wint_t __cdecl putwc (wint_t, FILE*);_CRTIMP int __cdecl _putws (constwchar_t*);_CRTIMP wint_t __cdecl putwchar (wint_t);_CRTIMP FILE* __cdecl _wfdopen(int,wchar_t*);_CRTIMP FILE* __cdecl _wfopen (constwchar_t*, constwchar_t*);_CRTIMP FILE* __cdecl _wfreopen (constwchar_t*, const wchar_t*, FILE*);_CRTIMP FILE* __cdecl _wfsopen (constwchar_t*, const wchar_t*, int);_CRTIMPwchar_t* __cdecl _wtmpnam (wchar_t*);_CRTIMPwchar_t* __cdecl _wtempnam (constwchar_t*, constwchar_t*);_CRTIMP int __cdecl _wrename (constwchar_t*, const wchar_t*);_CRTIMP int __cdecl _wremove (const wchar_t*);_CRTIMP void __cdecl _wperror (const wchar_t*);_CRTIMP FILE* __cdecl _wpopen (constwchar_t*, const wchar_t*);#endif /* __MSVCRT__ */#ifndef __NO_ISOCEXT /* externs in libmingwex.a */int __cdecl snwprintf (wchar_t* s, size_t n, const wchar_t* format, ...);__CRT_INLINE int __cdeclvsnwprintf (wchar_t* s, size_t n, const wchar_t* format, __VALIST arg){ return _vsnwprintf ( s, n, format, arg);}int __cdecl vwscanf (constwchar_t* __restrict__, __VALIST);int __cdecl vfwscanf (FILE * __restrict__,constwchar_t* __restrict__, __VALIST);int __cdecl vswscanf (constwchar_t* __restrict__,constwchar_t* __restrict__, __VALIST);#endif#define _WSTDIO_DEFINED#endif /* _WSTDIO_DEFINED */#ifndef __STRICT_ANSI__#ifdef __MSVCRT__#ifndef NO_OLDNAMES_CRTIMP FILE* __cdecl wpopen (const wchar_t*, const wchar_t*);#endif /* not NO_OLDNAMES */#endif /* MSVCRT runtime *//** Other Non ANSI wide functions*/_CRTIMP wint_t __cdecl _fgetwchar (void);_CRTIMP wint_t __cdecl _fputwchar (wint_t);_CRTIMP int __cdecl _getw (FILE*);_CRTIMP int __cdecl _putw(int, FILE*);#ifndef _NO_OLDNAMES_CRTIMP wint_t __cdecl fgetwchar (void);_CRTIMP wint_t __cdecl fputwchar (wint_t);_CRTIMP int __cdecl getw (FILE*);_CRTIMP int __cdeclputw(int, FILE*);#endif /* Not _NO_OLDNAMES */#endif /* __STRICT_ANSI */#ifdef __cplusplus}#endif#endif /* Not RC_INVOKED */#endif /* _STDIO_H_ */ stdio.h所包含的函数： 文件访问fopenfreopenfflushfclose二进制输入/输出freadfwrite非格式化输入/输出fgetc/getcfputc/putcungetcfgetsfputs格式化输入/输出scanf/fscanf/sscanfprintf/fprintf/sprintfperror文件定位ftellfseekfgetposfsetposrewind错误处理feofferror文件操作removerenametmpfile