readdir_r - Man Page

read a directory


#include <dirent.h>

int readdir_r(DIR *restrict dirp, struct dirent *restrict entry,
              struct dirent **restrict result);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):


        || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE


This function is deprecated; use readdir(3) instead.

The readdir_r() function was invented as a reentrant version of readdir(3). It reads the next directory entry from the directory stream dirp, and returns it in the caller-allocated buffer pointed to by entry. For details of the dirent structure, see readdir(3).

A pointer to the returned buffer is placed in *result; if the end of the directory stream was encountered, then NULL is instead returned in *result.

It is recommended that applications use readdir(3) instead of readdir_r(). Furthermore, since version 2.24, glibc deprecates readdir_r(). The reasons are as follows:

Return Value

The readdir_r() function returns 0 on success. On error, it returns a positive error number (listed under Errors). If the end of the directory stream is reached, readdir_r() returns 0, and returns NULL in *result.



Invalid directory stream descriptor dirp.


A directory entry whose name was too long to be read was encountered.


For an explanation of the terms used in this section, see attributes(7).

readdir_r()Thread safetyMT-Safe

Conforming to

POSIX.1-2001, POSIX.1-2008.

See Also



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Referenced By


2021-03-22 Linux Programmer's Manual