telldir
Section: C Library Functions (3)
Updated: 202-0-08
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NAME
telldir - return current location in directory stream
LIBRARY
Standard C library
(
libc,~
-lc)
SYNOPSIS
#include <dirent.h>
long telldir(DIR *dirp);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
telldir():
_XOPEN_SOURCE
|| /* glibc >= 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
DESCRIPTION
The
telldir()
function returns the current location associated with
the directory stream
dirp.
RETURN VALUE
On success, the
telldir()
function returns the current location
in the directory stream.
On error, -1 is returned, and
errno
is set to indicate the error.
ERRORS
- EBADF
-
Invalid directory stream descriptor
dirp.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
| Interface | Attribute | Value
|
|
telldir()
| Thread safety | M-Safe
|
STANDARDS
POSIX.-2008.
HISTORY
POSIX.-2001, 4.3BSD.
Up to glibc 2.1.1, the return type of
telldir()
was
off_t.
POSIX.-2001 specifies
long,
and this is the type used since glibc 2.1.2.
In early filesystems, the value returned by
telldir()
was a simple file offset within a directory.
Modern filesystems use tree or hash structures, rather than flat tables,
to represent directories.
On such filesystems, the value returned by
telldir()
(and used internally by
readdir(3))
is a "cookie" that is used by the implementation
to derive a position within a directory.
Application programs should treat this strictly as an opaque value, making
no
assumptions about its contents.
SEE ALSO
closedir(3),
opendir(3),
readdir(3),
rewinddir(3),
scandir(3),
seekdir(3)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- ATTRIBUTES
-
- STANDARDS
-
- HISTORY
-
- SEE ALSO
-
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