<title>stat/fstat/lstat functions.</title>
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<h1>stat/fstat/lstat functions.</h1>
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All three functions return information about a file. Please note
that devices are seen as files to Unix, so you could 'stat' things
like /dev/mouse to see when the mouse was last moved.<p>
<b>stat</b> return the status of a file.<p>
<b>fstat</b> stats an open file.<p>
<b>lstat</b> reports on a link, not the file it points too.<p>
<pre>
Libraries: sys/stat.h
unistd.h
Syntax: struct stat stat_p;
stat ("martin", &stat_p);
Stat Structure:
struct stat
{
dev_t st_dev; /* device */
ino_t st_ino; /* inode */
umode_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 */
};
</pre>
<b>st_mode</b> can be used with the following macros to discover the
type of file being statted.
<a name=filetype>
<pre>
S_ISLNK(st_mode) is it a symbolic link
S_ISREG(st_mode) regular file
S_ISDIR(st_mode) directory
S_ISCHR(st_mode) character device
S_ISBLK(st_mode) block device
S_ISFIFO(st_mode) fifo
S_ISSOCK(st_mode) socket
</pre>
These functions return a large amount of information. See the man page
(below) for details. You will need to understand
<a href="../SYNTAX/struct.html">structures</a> to work with stat.<p>
<img src=../../GRAPHICS/man.gif>
<a href="../MAN/stat.htm">
man page to provide all the details.</a>
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<h2>Examples</h2>
<img src=../../GRAPHICS/computer.gif>
<a href="../EXAMPLES/stat.c">
example program.</a>
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<h2>See also:</h2>
<img src=../../GRAPHICS/whiteball.gif>
<a href=directory.html>POSIX functions to read directory information.</a>
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<h2>Note</h2>
I have seen a problem with the 'access time', it only seems to get updated
if the file system is local. If the filesystem is NFS mounted and
accessed via 'cat' or 'head' the access date is not updated.
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<address>Martin Leslie
</address><p>
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