| .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
| .\" |
| .\" %%%LICENSE_START(VERBATIM) |
| .\" Permission is granted to make and distribute verbatim copies of this |
| .\" manual provided the copyright notice and this permission notice are |
| .\" preserved on all copies. |
| .\" |
| .\" Permission is granted to copy and distribute modified versions of this |
| .\" manual under the conditions for verbatim copying, provided that the |
| .\" entire resulting derived work is distributed under the terms of a |
| .\" permission notice identical to this one. |
| .\" |
| .\" Since the Linux kernel and libraries are constantly changing, this |
| .\" manual page may be incorrect or out-of-date. The author(s) assume no |
| .\" responsibility for errors or omissions, or for damages resulting from |
| .\" the use of the information contained herein. The author(s) may not |
| .\" have taken the same level of care in the production of this manual, |
| .\" which is licensed free of charge, as they might when working |
| .\" professionally. |
| .\" |
| .\" Formatted or processed versions of this manual, if unaccompanied by |
| .\" the source, must acknowledge the copyright and authors of this work. |
| .\" %%%LICENSE_END |
| .\" |
| .\" References consulted: |
| .\" Linux libc source code |
| .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) |
| .\" 386BSD man pages |
| .\" Modified Sat Jul 24 17:48:42 1993 by Rik Faith (faith@cs.unc.edu) |
| .TH TELLDIR 3 2021-03-22 "" "Linux Programmer's Manual" |
| .SH NAME |
| telldir \- return current location in directory stream |
| .SH SYNOPSIS |
| .nf |
| .B #include <dirent.h> |
| .PP |
| .BI "long telldir(DIR *" dirp ); |
| .fi |
| .PP |
| .RS -4 |
| Feature Test Macro Requirements for glibc (see |
| .BR feature_test_macros (7)): |
| .RE |
| .PP |
| .BR telldir (): |
| .nf |
| _XOPEN_SOURCE |
| || /* Glibc since 2.19: */ _DEFAULT_SOURCE |
| || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE |
| .fi |
| .SH DESCRIPTION |
| The |
| .BR telldir () |
| function returns the current location associated with |
| the directory stream \fIdirp\fP. |
| .SH RETURN VALUE |
| On success, the |
| .BR telldir () |
| function returns the current location |
| in the directory stream. |
| On error, \-1 is returned, and |
| .I errno |
| is set to indicate the error. |
| .SH ERRORS |
| .TP |
| .B EBADF |
| Invalid directory stream descriptor \fIdirp\fP. |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .ad l |
| .nh |
| .TS |
| allbox; |
| lbx lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR telldir () |
| T} Thread safety MT-Safe |
| .TE |
| .hy |
| .ad |
| .sp 1 |
| .SH CONFORMING TO |
| POSIX.1-2001, POSIX.1-2008, 4.3BSD. |
| .SH NOTES |
| In glibc up to version 2.1.1, the return type of |
| .BR telldir () |
| was |
| .IR off_t . |
| POSIX.1-2001 specifies |
| .IR long , |
| and this is the type used since glibc 2.1.2. |
| .PP |
| In early filesystems, the value returned by |
| .BR 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 |
| .BR telldir () |
| (and used internally by |
| .BR readdir (3)) |
| is a "cookie" that is used by the implementation |
| to derive a position within a directory. |
| .\" https://lwn.net/Articles/544298/ |
| Application programs should treat this strictly as an opaque value, making |
| .I no |
| assumptions about its contents. |
| .SH SEE ALSO |
| .BR closedir (3), |
| .BR opendir (3), |
| .BR readdir (3), |
| .BR rewinddir (3), |
| .BR scandir (3), |
| .BR seekdir (3) |
