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
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 indi-
cate the error.
ERRORS
EBADF Invalid directory stream descriptor dirp.
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(7).
┌────────────────────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├────────────────────────────────────────────┼───────────────┼─────────┤
│telldir() │ Thread safety │ MT-Safe │
└────────────────────────────────────────────┴───────────────┴─────────┘
STANDARDS
POSIX.1-2001, POSIX.1-2008, 4.3BSD.
NOTES
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 struc-
tures, 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 6.03 2023-02-05 telldir(3)
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