Node:Reading Attributes,
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Reading the Attributes of a File
To examine the attributes of files, use the functions stat
,
fstat
and lstat
. They return the attribute information in
a struct stat
object. All three functions are declared in the
header file sys/stat.h
.
int stat (const char *filename, struct stat *buf)
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Function |
The stat function returns information about the attributes of the
file named by filename in the structure pointed to by buf.
If filename is the name of a symbolic link, the attributes you get
describe the file that the link points to. If the link points to a
nonexistent file name, then stat fails reporting a nonexistent
file.
The return value is 0 if the operation is successful, or
-1 on failure. In addition to the usual file name errors
(see File Name Errors, the following errno error conditions
are defined for this function:
ENOENT
- The file named by filename doesn't exist.
When the sources are compiled with _FILE_OFFSET_BITS == 64 this
function is in fact stat64 since the LFS interface transparently
replaces the normal implementation.
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int stat64 (const char *filename, struct stat64 *buf)
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Function |
This function is similar to stat but it is also able to work on
files larger then 2^31 bytes on 32-bit systems. To be able to do
this the result is stored in a variable of type struct stat64 to
which buf must point.
When the sources are compiled with _FILE_OFFSET_BITS == 64 this
function is available under the name stat and so transparently
replaces the interface for small files on 32-bit machines.
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int fstat (int filedes, struct stat *buf)
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Function |
The fstat function is like stat , except that it takes an
open file descriptor as an argument instead of a file name.
See Low-Level I/O.
Like stat , fstat returns 0 on success and -1
on failure. The following errno error conditions are defined for
fstat :
EBADF
- The filedes argument is not a valid file descriptor.
When the sources are compiled with _FILE_OFFSET_BITS == 64 this
function is in fact fstat64 since the LFS interface transparently
replaces the normal implementation.
|
int fstat64 (int filedes, struct stat64 *buf)
|
Function |
This function is similar to fstat but is able to work on large
files on 32-bit platforms. For large files the file descriptor
filedes should be obtained by open64 or creat64 .
The buf pointer points to a variable of type struct stat64
which is able to represent the larger values.
When the sources are compiled with _FILE_OFFSET_BITS == 64 this
function is available under the name fstat and so transparently
replaces the interface for small files on 32-bit machines.
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int lstat (const char *filename, struct stat *buf)
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Function |
The lstat function is like stat , except that it does not
follow symbolic links. If filename is the name of a symbolic
link, lstat returns information about the link itself; otherwise
lstat works like stat . See Symbolic Links.
When the sources are compiled with _FILE_OFFSET_BITS == 64 this
function is in fact lstat64 since the LFS interface transparently
replaces the normal implementation.
|
int lstat64 (const char *filename, struct stat64 *buf)
|
Function |
This function is similar to lstat but it is also able to work on
files larger then 2^31 bytes on 32-bit systems. To be able to do
this the result is stored in a variable of type struct stat64 to
which buf must point.
When the sources are compiled with _FILE_OFFSET_BITS == 64 this
function is available under the name lstat and so transparently
replaces the interface for small files on 32-bit machines.
|