STAT(2) BSD System Calls Manual STAT(2)

     fstat, fstat64, lstat, lstat64, stat, stat64 -- get file status

     int fstat(int fildes, struct stat *buf); 
     int lstat(const char *restrict path, struct stat *restrict buf); 
     int  stat(const char *restrict path, struct stat *restrict buf); 
transitiional synopsis (now deprecated)
     int fstat64(int fildes, struct stat64 *buf); 
     int lstat64(const char *restrict path, struct stat64 *restrict buf); int
     stat64(const char *restrict path, struct stat64 *restrict buf);


The stat() function obtains information about the file pointed to by path. Read, write or execute permission of the file is not required, all directories in the path leading to the file must be searchable (x mode). lstat() returns information about the link where the named file is a symbolic link; stat() returns information about the file the link references. Symbolic links do not have an owner, group, access mode, times, etc., these attributes may be taken from the directory that contains the link. In this case, the only attributes returned from an lstat() that refer to the symbolic link itself are the file type (S_IFLNK), size, blocks, and link count (always 1). fstat() obtains information about an open file filedes buf is a pointer to a stat structure as defined by <sys/stat.h> where information is placed. struct stat { /* when _DARWIN_FEATURE_64_BIT_INODE is NOT defined */ dev_t st_dev; /* device inode resides on */ ino_t st_ino; /* inode's number 32 bits */ mode_t st_mode; /* inode protection mode */ nlink_t st_nlink; /* number of hard links to the file */ uid_t st_uid; /* user-id of owner */ gid_t st_gid; /* group-id of owner */ dev_t st_rdev; /* device type, for special file inode */ struct timespec st_atimespec; /* time of last access */ struct timespec st_mtimespec; /* time of last data modification */ struct timespec st_ctimespec; /* time of last file status change */ off_t st_size; /* file size, in bytes */ quad_t st_blocks; /* blocks allocated for file */ u_long st_blksize;/* optimal file sys I/O ops blocksize */ u_long st_flags; /* user defined flags for file */ u_long st_gen; /* file generation number */ }; struct stat { /* when _DARWIN_FEATURE_64_BIT_INODE is defined */ dev_t st_dev; /* ID of device containing file */ mode_t st_mode; /* Mode of file */ nlink_t st_nlink; /* Number of hard links */ ino_t st_ino; /* File serial number 64 bits */ uid_t st_uid; /* User ID of the file */ gid_t st_gid; /* Group ID of the file */ dev_t st_rdev; /* Device ID */ struct timespec st_atimespec; /* time of last access */ struct timespec st_mtimespec; /* time of last data modification */ struct timespec st_ctimespec; /* time of last status change */ struct timespec st_birthtimespec; /* time of file creation(birth) added */ off_t st_size; /* file size, in bytes */ blkcnt_t st_blocks; /* blocks allocated for file */ blksize_t st_blksize; /* optimal blocksize for I/O */ uint32_t st_flags; /* user defined flags for file */ uint32_t st_gen; /* file generation number */ int32_t st_lspare; /* RESERVED: DO NOT USE! */ int64_t st_qspare[2]; /* RESERVED: DO NOT USE! */ }; The time-related fields of struct stat are as follows: st_atime Time file data last accessed. Changed by the mknod, utimes and read st_mtime Time file data last modified. Changed by the mknod, utimes and write st_ctime Time file status was last changed (inode data modification). Changed by the chmod, chown, link, mknod, rename, unlink, utimes and write st_birthtime Time of file creation. Only available in the 64 bit inode variants. Where birthtime is not available, this field holds the ctime st_blksize optimal I/O block size for the file. st_blocks number of blocks allocated for the file in 512-byte units. May be zero for symblolic links. st_mode : #define S_IFMT 0170000 /* type of file */ #define S_IFIFO 0010000 /* named pipe (fifo) */ #define S_IFCHR 0020000 /* character special */ #define S_IFDIR 0040000 /* directory */ #define S_IFBLK 0060000 /* block special */ #define S_IFREG 0100000 /* regular */ #define S_IFLNK 0120000 /* symbolic link */ #define S_IFSOCK 0140000 /* socket */ #define S_IFWHT 0160000 /* whiteout */ #define S_ISUID 0004000 /* set user id on execution */ #define S_ISGID 0002000 /* set group id on execution */ #define S_ISVTX 0001000 /* save swapped text even after use (sticky) */ #define S_IRUSR 0000400 /* read permission, owner */ #define S_IWUSR 0000200 /* write permission, owner */ #define S_IXUSR 0000100 /* execute/search permission, owner */ For a list of access modes, see <sys/stat.h> access and chmod. For a list of the file flags in the st_flags field, see <sys/stat.h> and chflags. _DARWIN_FEATURE_64_BIT_INODE In order to accommodate advanced capabilities of newer file systems, the struct stat, struct statfs, and struct dirent data structures were updated in Mac OSX 10.5. ino_t increased from 32 bits to 64 bits. storing an ino_t in an int is no longer valid and must be updated. f_fstypename, f_mntonname, and f_mntfromname in struct statfs are widen. See to stat(2) and dir(5) for more detail on the specific changes to the other affected data structures. On platforms that existed before these updates were available, ABI compatibility is achieved by providing two implementations for related functions. Variants which make use of the newer structures have their symbols suffixed with $INODE64, are automatically appended by the compiler tool-chain and should not be used directly. Platforms that were released after these updates only have the newer variants available to them and have the macro _DARWIN_FEATURE_ONLY_64_BIT_INODE defined. _DARWIN_FEATURE_64_BIT_INODE macro should not be set directly, use _DARWIN_NO_64_BIT_INODE or _DARWIN_USE_64_BIT_INODE macros when the default variant is not desired. The following table details the effects of defining these macros for different deployment targets. _DARWIN_FEATURE_ONLY_64_BIT_INODE not defined -------------------------+------------------------------- | Deployment Target user defines: | < 10.5 10.5 > 10.5 -------------------------+------------------------------- (none) | 32-bit 32-bit 64-bit _DARWIN_NO_64_BIT_INODE | 32-bit 32-bit 32-bit _DARWIN_USE_64_BIT_INODE | 32-bit 64-bit 64-bit -------------------------+------------------------------- _DARWIN_FEATURE_ONLY_64_BIT_INODE defined -------------------------+------------------------------- user defines: | Any Deployment Target -------------------------+------------------------------- (none) | 64-bit-only _DARWIN_NO_64_BIT_INODE | (error) _DARWIN_USE_64_BIT_INODE | 64-bit-only -------------------------+------------------------------- 32-bit 32-bit inode values are enabled, and the legacy structures involving the ino_t type are in use. The macro _DARWIN_FEATURE_64_BIT_INODE is not defined. 64-bit 64-bit inode values are enabled, and the expanded structures involving the ino_t type are in use. The macro _DARWIN_FEATURE_64_BIT_INODE is defined, and loader symbols will contain the $INODE64 suffix. 64-bit-only Like 64-bit, except loader symbols do not have the $INODE64 suffix. (error) A compile time error is generated. Due to the increased benefits of the larger structure, it is highly recommended that developers not define _DARWIN_NO_64_BIT_INODE and make use of _DARWIN_USE_64_BIT_INODE when targeting Mac OSX 10.5. In addition to the $INODE64 suffixed symbols, variants suffixed with 64 are also available for related functions. These functions were provided as a way for developers to use the updated structures in code that also made use of the legacy structures. The enlarged stat structures were also prefixed with 64 to distinguish them from their legacy variants. These functions have been deprecated and should be avoided. RETURN VALUES Upon successful completion a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error. COMPATIBILITY Previous versions of the system used different types for the st_dev, st_uid, st_gid, st_rdev, st_size, st_blksize and st_blocks fields. ERRORS fstat() system call will fail if: [EBADF] fildes is not a valid open file descriptor. [EFAULT] Sb points to an invalid address. [EIO] An I/O error occurs while reading from or writing to the file system. lstat() and stat() system calls will fail if: [EACCES] Search permission is denied for a component of the path prefix. [EFAULT] Sb or name points to an invalid address. [EIO] An I/O error occurs while reading from or writing to the file system. [ELOOP] Too many symbolic links are encountered in translating the pathname, indicative of a looping symbolic link. [ENAMETOOLONG] A component of a pathname exceeds {NAME_MAX} characters, or an entire path name exceeds {PATH_MAX} characters. [ENOENT] The named file does not exist. [ENOTDIR] A component of the path prefix is not a directory. fstat(), lstat(), and stat() system calls will fail if: [EOVERFLOW] The file size in bytes, the number of blocks allocated to the file or the file serial number cannot be represented correctly in the structure pointed to by buf. CAVEATS The file generation number, st_gen, is only available to the super-user. The fields in the stat structure currently marked st_spare1, st_spare2, and st_spare3 are present in preparation for inode time stamps expanding to 64 bits. This breaks certain programs that depend on the time stamps being contiguous (in calls to utimes(2))! TRANSITIONAL DESCRIPTION (NOW DEPRECATED) The fstat64, lstat64 and stat64 routines are equivalent to their corresponding non-64-suffixed routine, when 64-bit inodes are in effect. They were added before there was support for the symbol variants, and so are now deprecated. Instead of using these, set the _DARWIN_USE_64_BIT_INODE macro before including header files to force 64-bit inode support. The stat64 structure used by these deprecated routines is the same as the stat structure when 64-bit inodes are in effect SEE ALSO chflags(2), chmod(2), chown(2), utimes(2), compat(5), statfs(2), symlink(7) BUGS Applying fstat to a socket (and thus to a pipe) returns a zero'd buffer, except for the blocksize field, and a unique device and inode number. STANDARDS The stat() and fstat() function calls are expected to conform to IEEE Std 1003.1-1988 (POSIX.1). HISTORY An lstat() function call appeared in 4.2BSD. stat64(), fstat64(), and lstat64() system calls first appeared in Mac OS X 10.5 (Leopard) and are now deprecated in favor of the corresponding symbol variants.