user-0 提问: 求解有没有一个能返回文件长度的函数 

回复:
user: user-1
content: STAT Section: Linux Programmer's Manual (2) Updated: 2004-06-23  --------------------------------------------------------------------------------    NAME stat, fstat, lstat - get file status    SYNOPSIS #include <sys/types.h>  #include <sys/stat.h>  #include <unistd.h>  int stat(const char *file_name, struct stat *buf);  int fstat(int filedes, struct stat *buf);  int lstat(const char *file_name, struct stat *buf);     DESCRIPTION These functions return information about the specified file. You do not need any access rights to the file to get this information but you need search rights to all directories named in the path leading to the file.   stat stats the file pointed to by file_name and fills in buf.   lstat is identical to stat, except in the case of a symbolic link, where the link itself is stat-ed, not the file that it refers to.   fstat is identical to stat, only the open file pointed to by filedes (as returned by open(2)) is stat-ed in place of file_name.    They all return a stat structure, which contains the following fields:    struct stat {     dev_t         st_dev;      /* device */     ino_t         st_ino;      /* inode */     mode_t        st_mode;     /* protection */     nlink_t       st_nlink;    /* number of hard links */     uid_t         st_uid;      /* user ID of owner */     gid_t         st_gid;      /* group ID of owner */     dev_t         st_rdev;     /* device type (if inode device) */     off_t         st_size;     /* total size, in bytes */     blksize_t     st_blksize;  /* blocksize for filesystem I/O */     blkcnt_t      st_blocks;   /* number of blocks allocated */     time_t        st_atime;    /* time of last access */     time_t        st_mtime;    /* time of last modification */     time_t        st_ctime;    /* time of last status change */ };  The value st_size gives the size of the file (if it is a regular file or a symlink) in bytes. The size of a symlink is the length of the pathname it contains, without trailing NUL.   The value st_blocks gives the size of the file in 512-byte blocks. (This may be smaller than st_size/512 e.g. when the file has holes.) The value st_blksize gives the "preferred" blocksize for efficient file system I/O. (Writing to a file in smaller chunks may cause an inefficient read-modify-rewrite.)   Not all of the Linux filesystems implement all of the time fields. Some file system types allow mounting in such a way that file accesses do not cause an update of the st_atime field. (See `noatime' in mount(8).)   The field st_atime is changed by file accesses, e.g. by execve(2), mknod(2), pipe(2), utime(2) and read(2) (of more than zero bytes). Other routines, like mmap(2), may or may not update st_atime.   The field st_mtime is changed by file modifications, e.g. by mknod(2), truncate(2), utime(2) and write(2) (of more than zero bytes). Moreover, st_mtime of a directory is changed by the creation or deletion of files in that directory. The st_mtime field is not changed for changes in owner, group, hard link count, or mode.   The field st_ctime is changed by writing or by setting inode information (i.e., owner, group, link count, mode, etc.).   The following POSIX macros are defined to check the file type using the st_mode field:   S_ISREG(m) is it a regular file?  S_ISDIR(m) directory?  S_ISCHR(m) character device?  S_ISBLK(m) block device?  S_ISFIFO(m) fifo?  S_ISLNK(m) symbolic link? (Not in POSIX.1-1996.)  S_ISSOCK(m) socket? (Not in POSIX.1-1996.)  The following flags are defined for the st_mode field: S_IFMT 0170000 bitmask for the file type bitfields   S_IFSOCK 0140000 socket   S_IFLNK 0120000 symbolic link   S_IFREG 0100000 regular file   S_IFBLK 0060000 block device   S_IFDIR 0040000 directory   S_IFCHR 0020000 character device   S_IFIFO 0010000 fifo   S_ISUID 0004000 set UID bit   S_ISGID 0002000 set GID bit (see below)   S_ISVTX 0001000 sticky bit (see below)   S_IRWXU 00700 mask for file owner permissions   S_IRUSR 00400 owner has read permission   S_IWUSR 00200 owner has write permission   S_IXUSR 00100 owner has execute permission   S_IRWXG 00070 mask for group permissions   S_IRGRP 00040 group has read permission   S_IWGRP 00020 group has write permission   S_IXGRP 00010 group has execute permission   S_IRWXO 00007 mask for permissions for others (not in group)   S_IROTH 00004 others have read permission   S_IWOTH 00002 others have write permisson   S_IXOTH 00001 others have execute permission   The set GID bit (S_ISGID) has several special uses: For a directory it indicates that BSD semantics is to be used for that directory: files created there inherit their group ID from the directory, not from the effective group ID of the creating process, and directories created there will also get the S_ISGID bit set. For a file that does not have the group execution bit (S_IXGRP) set, it indicates mandatory file/record locking. The `sticky' bit (S_ISVTX) on a directory means that a file in that directory can be renamed or deleted only by the owner of the file, by the owner of the directory, and by a privileged process.     RETURN VALUE On success, zero is returned. On error, -1 is returned, and errno is set appropriately.    ERRORS EACCES  Search permission is denied for one of the directories in the path prefix of file_name. (See also path_resolution(2).)  EBADF  filedes is bad.  EFAULT  Bad address.  ELOOP  Too many symbolic links encountered while traversing the path.  ENAMETOOLONG  File name too long.  ENOENT  A component of the path file_name does not exist, or the path is an empty string.  ENOMEM  Out of memory (i.e. kernel memory).  ENOTDIR  A component of the path is not a directory.     CONFORMING TO The stat and fstat calls conform to SVr4, SVID, POSIX, X/OPEN, BSD 4.3. The lstat call conforms to 4.3BSD and SVr4. SVr4 documents additional fstat error conditions EINTR, ENOLINK, and EOVERFLOW. SVr4 documents additional stat and lstat error conditions EINTR, EMULTIHOP, ENOLINK, and EOVERFLOW. Use of the st_blocks and st_blksize fields may be less portable. (They were introduced in BSD. Are not specified by POSIX. The interpretation differs between systems, and possibly on a single system when NFS mounts are involved.)  POSIX does not describe the S_IFMT, S_IFSOCK, S_IFLNK, S_IFREG, S_IFBLK, S_IFDIR, S_IFCHR, S_IFIFO, S_ISVTX bits, but instead demands the use of the macros S_ISDIR(), etc. The S_ISLNK and S_ISSOCK macros are not in POSIX.1-1996, but both will be in the next POSIX standard; the former is from SVID 4v2, the latter from SUSv2.   Unix V7 (and later systems) had S_IREAD, S_IWRITE, S_IEXEC, where POSIX prescribes the synonyms S_IRUSR, S_IWUSR, S_IXUSR.     OTHER SYSTEMS Values that have been (or are) in use on various systems: hex name ls octal description   f000 S_IFMT  170000 mask for file type   0000   000000 SCO out-of-service inode, BSD unknown type       SVID-v2 and XPG2 have both 0 and 0100000 for ordinary file   1000 S_IFIFO p| 010000 fifo (named pipe)   2000 S_IFCHR c 020000 character special (V7)   3000 S_IFMPC  030000 multiplexed character special (V7)   4000 S_IFDIR d/ 040000 directory (V7)   5000 S_IFNAM  050000 XENIX named special file       with two subtypes, distinguished by st_rdev values 1, 2:   0001 S_INSEM s 000001 XENIX semaphore subtype of IFNAM   0002 S_INSHD m 000002 XENIX shared data subtype of IFNAM   6000 S_IFBLK b 060000 block special (V7)   7000 S_IFMPB  070000 multiplexed block special (V7)   8000 S_IFREG - 100000 regular (V7)   9000 S_IFCMP  110000 VxFS compressed   9000 S_IFNWK n 110000 network special (HP-UX)   a000 S_IFLNK l@ 120000 symbolic link (BSD)   b000 S_IFSHAD  130000 Solaris shadow inode for ACL (not seen by userspace)   c000 S_IFSOCK s= 140000 socket (BSD; also "S_IFSOC" on VxFS)   d000 S_IFDOOR D> 150000 Solaris door   e000 S_IFWHT w% 160000 BSD whiteout (not used for inode)          0200 S_ISVTX  001000 `sticky bit': save swapped text even after use (V7)       reserved (SVID-v2)       On non-directories: don't cache this file (SunOS)       On directories: restricted deletion flag (SVID-v4.2)   0400 S_ISGID  002000 set group ID on execution (V7)       for directories: use BSD semantics for propagation of gid   0400 S_ENFMT  002000 SysV file locking enforcement (shared w/ S_ISGID)   0800 S_ISUID  004000 set user ID on execution (V7)   0800 S_CDF  004000 directory is a context dependent file (HP-UX)    A sticky command appeared in Version 32V AT&T UNIX.       SEE ALSO chmod(2), chown(2), readlink(2), utime(2), capabilities(7)  --------------------------------------------------------------------------------

user: user-1
content: _stat, _wstat, _stati64, _wstati64 Get status information on a file.  int _stat( const char *path, struct _stat *buffer );  __int64 _stati64( const char *path, struct _stat *buffer );  int _wstat( const wchar_t *path, struct _stat *buffer );  __int64 _wstati64( const wchar_t *path, struct _stat *buffer );  Routine Required Header Optional Headers Compatibility  _stat <sys/types.h> followed by <sys/stat.h> <errno.h> Win 95, Win NT  _wstat <sys/types.h> followed by <sys/stat.h> or <wchar.h> <errno.h> Win NT  _stati64 <sys/types.h> followed by <sys/stat.h> <errno.h> Win 95, Win NT  _wstati64 <sys/types.h> followed by <sys/stat.h> or <wchar.h> <errno.h> Win NT    For additional compatibility information, see Compatibility in the Introduction.  Libraries  LIBC.LIB Single thread static library, retail version  LIBCMT.LIB Multithread static library, retail version  MSVCRT.LIB Import library for MSVCRT.DLL, retail version    Return Value  Each of these functions returns 0 if the file-status information is obtained. A return value of –1 indicates an error, in which case errno is set to ENOENT, indicating that the filename or path could not be found.  Parameters  path  Path of existing file  buffer  Pointer to structure that stores results  Remarks  The _stat function obtains information about the file or directory specified by path and stores it in the structure pointed to by buffer. _stat automatically handles multibyte-character string arguments as appropriate, recognizing multibyte-character sequences according to the multibyte code page currently in use.   _wstat is a wide-character version of _stat; the path argument to _wstat is a wide-character string. _wstat and _stat behave identically except that _wstat does not handle multibyte-character strings.  Generic-Text Routine Mappings  TCHAR.H Routine  _UNICODE & _MBCS Not Defined _MBCS Defined _UNICODE Defined  _tstat _stat _stat _wstat  _tstati64 _stati64 _stati64 _wstati64    The _stat structure, defined in SYS\STAT.H, includes the following fields.  st_gid  Numeric identifier of group that owns file (UNIX-specific) This field will always be zero on NT systems. A redirected file is classified as an NT file.  st_atime  Time of last access of file.  st_ctime  Time of creation of file.  st_dev  Drive number of the disk containing the file (same as st_rdev).  st_ino  Number of the information node (the inode) for the file (UNIX-specific). On UNIX file systems, the inode describes the file date and time stamps, permissions, and content. When files are hard-linked to one another, they share the same inode. The inode, and therefore st_ino, has no meaning in the FAT, HPFS, or NTFS file systems.  st_mode  Bit mask for file-mode information. The _S_IFDIR bit is set if path specifies a directory; the _S_IFREG bit is set if path specifies an ordinary file or a device. User read/write bits are set according to the file’s permission mode; user execute bits are set according to the filename extension.  st_mtime  Time of last modification of file.  st_nlink  Always 1 on non-NTFS file systems.  st_rdev  Drive number of the disk containing the file (same as st_dev).  st_size  Size of the file in bytes; a 64-bit integer for _stati64 and _wstati64  st_uid  Numeric identifier of user who owns file (UNIX-specific). This field will always be zero on NT systems. A redirected file is classified as an NT file.  If path refers to a device, the size, time, _dev, and _rdev fields in the _stat structure are meaningless. Because STAT.H uses the _dev_t type that is defined in TYPES.H, you must include TYPES.H before STAT.H in your code.  Example   /* STAT.C: This program uses the _stat function to  * report information about the file named STAT.C.  */  #include <time.h> #include <sys/types.h> #include <sys/stat.h> #include <stdio.h>  void main( void ) {    struct _stat buf;    int result;    char buffer[] = "A line to output";     /* Get data associated with "stat.c": */    result = _stat( "stat.c", &buf );     /* Check if statistics are valid: */    if( result != 0 )       perror( "Problem getting information" );    else    {       /* Output some of the statistics: */       printf( "File size     : %ld\n", buf.st_size );       printf( "Drive         : %c:\n", buf.st_dev + 'A' );       printf( "Time modified : %s", ctime( &buf.st_atime ) );    } }   Output  File size     : 745 Drive         : C: Time modified : Tue May 03 00:00:00 1994   File Handling Routines  See Also   _access, _fstat, _getmbcp, _setmbcp

user: user-2
content: 引用 2 楼 max_min_ 的回复:#include <stdio.h>  int main()  {    FILE *fp;    char filename[80];    long length;    printf("输入文件名:");    gets(filename);    //以二进制读文件方式打开文件    fp=fopen(filename,"rb");    if(fp==NULL)       printf("file not found!\n");    else       {         //把文件的位置指针移到文件尾           fseek(fp,OL,SEEK_END);          //获取文件长度;           length=ftell(fp);           printf("该文件的长度为%1d字节\n",length);           fclose(fp);        }  }   获取文件大小，网上很多的！ 支持版主的源码解答，比直接掉库函数要学到的东西多

user: user-3
content: Win32下，DWORD GetFileSize( HANDLE hFile, DWORD * dwHightDword );

user: user-4
content: #include <stdio.h>  int main()  {    FILE *fp;    char filename[80];    long length;    printf("输入文件名:");    gets(filename);    //以二进制读文件方式打开文件    fp=fopen(filename,"rb");    if(fp==NULL)       printf("file not found!\n");    else       {         //把文件的位置指针移到文件尾           fseek(fp,OL,SEEK_END);          //获取文件长度;           length=ftell(fp);           printf("该文件的长度为%1d字节\n",length);           fclose(fp);        }  }   获取文件大小，网上很多的！

user: user-5
content: 自己封装一个吧 windows还是Linux