telldir(3) Library Functions Manual telldir(3) NAME telldir - return current location in directory stream LIBRARY Standard C library (libc, -lc) SYNOPSIS #include 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 | 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 6.7 2023-10-31 telldir(3)