telldir(3)		    Library Functions Manual		      telldir(3)

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 di-
     rectory stream dirp.

RETURN VALUE
     On	 success, the telldir() function returns the current location in the di-
     rectory 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).
     allbox; lbx lb lb l l l.  Interface Attribute Value T{ telldir()
     T}	  Thread safety	  MT-Safe

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)

Linux man-pages 6.18		   2026-02-08			      telldir(3)