telldir(3)

NAME#

telldir - return current location in directory stream

LIBRARY#

Standard C library (libc, -lc)

SYNOPSIS#

#include <dirent.h>

long telldir(DIR *\ndirp\n);

telldir():

\n
    _XOPEN_SOURCE
\n
       || /* glibc >= 2.19: */ _DEFAULT_SOURCE
\n
       || /* 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).

STANDARDS#

POSIX.1-2008.

HISTORY#

POSIX.1-2001, 4.3BSD.

Up to glibc 2.1.1, the return type of telldir() was off_t. POSIX.1-2001 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)