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stat(2)
NAME
stat, fstat, lstat - Provides information about a file
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
int stat(
const char *path,
struct stat *buffer );
int lstat(
const char *path,
struct stat *buffer );
int fstat(
int filedes,
struct stat *buffer );
STANDARDS
Interfaces documented on this reference page conform to industry standards
as follows:
fstat(): POSIX.1, XSH5.0
lstat(): POSIX.1, XSH5.0
stat(): POSIX.1, XSH5.0
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
PARAMETERS
path Specifies the pathname identifying the file.
filedes Specifies the file descriptor identifying the open file.
buffer Points to the stat structure in which information is returned.
The stat structure is described in the <sys/stat.h> header file.
DESCRIPTION
The stat() function obtains information about the file named by the path
parameter. Read, write, or execute permission for the named file is not
required, but all directories listed in the pathname leading to the file
must be searchable. The file information is written to the area specified
by the buffer parameter, which is a pointer to a stat structure, defined in
sys/stat.h.
The values of the stat structure's member, mode_t, are defined in
<sys/mode.h>.
The fstat() function is like the stat() function except that the
information obtained is about an open file referenced by the filedes
parameter.
The lstat() function is like the stat() function except in the case where
the named file is a symbolic link. In this case, the lstat() function
returns information about the link, while the stat() and fstat() functions
return information about the file the link references. In the case of a
symbolic link, the stat() functions set the st_size field of the stat
structure to the length of the symbolic link, and sets the st_mode field to
indicate the file type.
The stat(), lstat(), and fstat() functions update any time-related fields
associated with the file before writing into the stat structure.
[Tru64 UNIX] When run on a file in an AdvFS clone fileset, the value
returned for st_blocks is the number of blocks in the original file at the
time the clone fileset was created.
NOTES
Two structure members in <stat.h> uniquely identify a file in a file
system: st_ino, the file serial number, and st_dev, the device id for the
directory that contains the file.
[Tru64 UNIX] However, in the rare case when a user application has been
deleting open files, and a file serial number is reused, a third structure
member in <stat.h>, the file generation number, is needed to uniquely
identify a file. This member, st_gen, is used in addition to st_ino and
st_dev.
RETURN VALUES
Upon successful completion, a value of 0 (zero) is returned. Otherwise, a
value of -1 is returned and errno is set to indicate the error.
ERRORS
If the stat() or lstat() function fails, errno may be set to one of the
following values:
[EACCES] Search permission is denied for a component of the path
parameter.
[EFAULT] Either the buffer parameter or the path parameter points to a
location outside of the allocated address space of the process.
[EIO] An I/O error occurred while reading from the file system.
[ELOOP] Too many links were encountered in translating path.
[ENAMETOOLONG]
The length of the path parameter exceeds PATH_MAX or a pathname
component is longer than NAME_MAX.
[ENOENT] The file named by the path parameter does not exist or is an
empty string.
[ENOTDIR] A component of the path parameter is not a directory.
[EOVERFLOW]
[Tru64 UNIX] The structure pointed to by the buffer argument
cannot correctly represent the value to be returned.
This error occurs in applications compiled either on a system
earlier than Tru64 UNIX Version 5.0 or on any system while using
the __V40_OBJ_COMPAT compiler macro. These applications use a
<statfs> structure for the for st_blocks fields that is not
compatible with the same structure in Tru64 UNIX Version 5.0.
[Tru64 UNIX] For NFS file access, if the stat() or lstat() function fails,
errno may also be set to one of the following values:
[EINVAL] The file position pointer associated with the filedes parameter
was negative.
[EISDIR] Indicates either that the request was for a write access to a
file but the specified filename was actually a directory, or that
the function was trying to rename a directory as a file.
[ENFILE] Indicates either that the system file table is full, or that
there are too many files currently open in the system.
[ESTALE] Indicates a stale NFS file handle. An opened file was deleted by
the server or another client; a client cannot open a file because
the server has unmounted or unexported the remote directory; or
the directory that contains an opened file was either unmounted
or unexported by the server.
If the fstat() function fails, errno may be set to one of the following
values:
[EBADF] The filedes parameter is not a valid file descriptor.
[EFAULT] The buffer parameter points to a location outside of the
allocated address space of the process.
[EIO] An I/O error occurred while reading from the file system.
[EOVERFLOW]
[Tru64 UNIX] The structure pointed to by the buffer argument
cannot correctly represent the value to be returned.
This error occurs in applications compiled either on a system
earlier than Tru64 UNIX Version 5.0 or or on any system while
using the __V40_OBJ_COMPAT compiler macro. These applications
use a <statfs> structure for st_blocks fields that is not
compatible with the same structure in Tru64 UNIX Version 5.0 or
later.
RELATED INFORMATION
Functions: chmod(2), chown(2), link(2), mknod(2), open(2), pipe(2),
symlink(2), utime(2)
Standards: standards(5)
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