STAT Section: System calls (2) Updated: May 13, 2025 Index   NAME stat, fstat, lstat - get file status   SYNOPSIS #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, only the link itself is stated, not the file that is obtained by tracing the links. fstat is identical to stat, only the open file pointed to by filedes (as returned by is stated 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 */ unsigned long st_blksize; /* blocksize for filesystem I/O */ unsigned long 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 change */ }; The value st_blocks gives the size of the file in 512-byte blocks. 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. Traditionally, st_atime is changed by Traditionally, st_mtime is changed by The st_mtime is not changed for changes in owner, group, hard link count, or mode. Traditionally, 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: S_ISLNK(m) is it a symbolic link? S_ISREG(m) regular file? S_ISDIR(m) directory? S_ISCHR(m) character device? S_ISBLK(m) block device? S_ISFIFO(m) fifo? S_ISSOCK(m) socket? The following flags are defined for the st_mode field: S_IFMT 00170000 bitmask for the file type bitfields (not POSIX) S_IFSOCK 0140000 socket (not POSIX) S_IFLNK 0120000 symbolic link (not POSIX) S_IFREG 0100000 regular file (not POSIX) S_IFBLK 0060000 block device (not POSIX) S_IFDIR 0040000 directory (not POSIX) S_IFCHR 0020000 character device (not POSIX) S_IFIFO 0010000 fifo (not POSIX) S_ISUID 0004000 set UID bit S_ISGID 0002000 set GID bit S_ISVTX 0001000 sticky bit (not POSIX) S_IRWXU 00700 user (file owner) has read, write and execute permission S_IRUSR 00400 user has read permission (same as S_IREAD, which is not POSIX) S_IWUSR 00200 user has write permission (same as S_IWRITE, which is not POSIX) S_IXUSR 00100 user has execute permission (same as S_IEXEC, which is not POSIX) S_IRWXG 00070 group has read, write and execute permission S_IRGRP 00040 group has read permission S_IWGRP 00020 group has write permission S_IXGRP 00010 group has execute permission S_IRWXO 00007 others have read, write and execute permission S_IROTH 00004 others have read permission S_IWOTH 00002 others have write permisson S_IXOTH 00001 others have execute permission   RETURN VALUE On success, zero is returned. On error, -1 is returned, and errno is set appropriately.   ERRORS EBADF filedes is bad. ENOENT A component of the path file_name does not exist, or the path is an empty string. ENOTDIR A component of the path is not a directory. ELOOP Too many symbolic links encountered while traversing the path. EFAULT Bad address. EACCES Permission denied. ENOMEM Out of memory (i.e. kernel memory). ENAMETOOLONG File name too long.   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 EACCES, 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.)   SEE ALSO utime (2)   Index NAME SYNOPSIS DESCRIPTION RETURN VALUE ERRORS CONFORMING TO SEE ALSO This document was created by using the manual pages. Time: 11:56:05 GMT, March 24, 2025