--- name: "getdents" section: "2" platform: "linux" package: "man-pages" version: "6.19-1" release: "Arch Linux 2026-11-01" platforms: ["linux", "freebsd"] url: "https://new.carta.tech/getdents" --- # getdents(2) get directory entries ## NAME getdents, getdents64 - get directory entries ## LIBRARY Standard C library (*libc*, *-lc*) ## SYNOPSIS ``` #include /* Definition of SYS_* constants */ #include ``` **long syscall(SYS\_getdents, unsigned int** *fd***, struct linux\_dirent \****dirp***,** **unsigned int** *count***);** **#define \_GNU\_SOURCE** /\* See [feature\_test\_macros(7)](/feature_test_macros/7.md) \*/ **#include \** **ssize\_t getdents64(**size\_t count; **int** *fd***, void** *dirp***\[***count***\], size\_t** *count***);** *Note*: glibc provides no wrapper for **getdents**(), necessitating the use of [**syscall**(2)](/syscall/2.md). *Note*: There is no definition of *struct linux\_dirent* in glibc; see NOTES. ## DESCRIPTION These are not the interfaces you are interested in. Look at [**readdir**(3)](/readdir/3.md) for the POSIX-conforming C library interface. ### getdents() The system call **getdents**() reads several *linux\_dirent* structures from the directory referred to by the open file descriptor *fd* into the buffer pointed to by *dirp*. The argument *count* specifies the size of that buffer. The *linux\_dirent* structure is declared as follows: ``` struct linux_dirent { unsigned long d_ino; /* Inode number */ unsigned long d_off; /* Not an offset; see below */ unsigned short d_reclen; /* Length of this linux_dirent */ char d_name[]; /* Filename (null-terminated) */ /* length is actually (d_reclen - 2 - offsetof(struct linux_dirent, d_name)) */ /* char pad; // Zero padding byte char d_type; // File type (only since Linux // 2.6.4); offset is (d_reclen - 1) */ } ``` *d\_ino* is an inode number. *d\_off* is a filesystem-specific value with no specific meaning to user space, though on older filesystems it used to be the distance from the start of the directory to the start of the next *linux\_dirent*; see [**readdir**(3)](/readdir/3.md). *d\_reclen* is the size of this entire *linux\_dirent*. *d\_name* is a null-terminated filename. *d\_type* is a byte at the end of the structure that indicates the file type. It contains one of the following values (defined in *\*): - **DT\_BLK** This is a block device. - **DT\_CHR** This is a character device. - **DT\_DIR** This is a directory. - **DT\_FIFO** This is a named pipe (FIFO). - **DT\_LNK** This is a symbolic link. - **DT\_REG** This is a regular file. - **DT\_SOCK** This is a UNIX domain socket. - **DT\_UNKNOWN** The file type is unknown. The *d\_type* field is implemented since Linux 2.6.4. It occupies a space that was previously a zero-filled padding byte in the *linux\_dirent* structure. Thus, on kernels up to and including Linux 2.6.3, attempting to access this field always provides the value 0 (**DT\_UNKNOWN**). Currently, only some filesystems (among them: Btrfs, ext2, ext3, and ext4) have full support for returning the file type in *d\_type*. All applications must properly handle a return of **DT\_UNKNOWN**. ### getdents64() The original Linux **getdents**() system call did not handle large filesystems and large file offsets. Consequently, Linux 2.4 added **getdents64**(), with wider types for the *d\_ino* and *d\_off* fields. In addition, **getdents64**() supports an explicit *d\_type* field. The **getdents64**() system call is like **getdents**(), except that its second argument is a pointer to a buffer containing structures of the following type: ``` struct linux_dirent64 { ino64_t d_ino; /* 64-bit inode number */ loff_t d_off; /* Not an offset; see getdents() */ unsigned short d_reclen; /* Size of this dirent */ unsigned char d_type; /* File type */ char d_name[]; /* Filename (null-terminated) */ }; ``` ## RETURN VALUE On success, the number of bytes read is returned. On end of directory, 0 is returned. On error, -1 is returned, and *errno* is set to indicate the error. ## ERRORS - **EBADF** Invalid file descriptor *fd*. - **EFAULT** Argument points outside the calling process's address space. - **EINVAL** Result buffer is too small. - **ENOENT** No such directory. - **ENOTDIR** File descriptor does not refer to a directory. ## STANDARDS None. ## HISTORY - **getdents**() SVr4. - **getdents64**() glibc 2.30. ## NOTES glibc does not provide a wrapper for **getdents**(); call **getdents**() using [**syscall**(2)](/syscall/2.md). In that case you will need to define the *linux\_dirent* structure yourself. The **getdents64**() system call accepts an **unsigned int** argument *count* and assumes that *count* does not exceed **INT\_MAX**. The glibc wrapper function sets *count* to **INT\_MAX** if it exceeds **INT\_MAX**. glibc defines a *dirent64* structure, which is similar to *linux\_dirent64* but with a 256-byte *d\_name*. Probably, you want to use [**readdir**(3)](/readdir/3.md) instead of these system calls. These calls supersede [**readdir**(2)](/readdir/2.md). ## EXAMPLES The program below demonstrates the use of **getdents**(). The following output shows an example of what we see when running this program on an ext2 directory: ``` $ ./a.out /testfs/ --------------- nread=120 --------------- inode# file type d_reclen d_off d_name 2 directory 16 12 . 2 directory 16 24 .. 11 directory 24 44 lost+found 12 regular 16 56 a 228929 directory 16 68 sub 16353 directory 16 80 sub2 130817 directory 16 4096 sub3 ``` ### Program source ``` #define _GNU_SOURCE #include /* Defines DT_* constants */ #include #include #include #include #include #include #include #include struct linux_dirent { unsigned long d_ino; off_t d_off; unsigned short d_reclen; char d_name[]; }; #define BUF_SIZE 1024 int main(int argc, char *argv[]) { int fd; char d_type; char buf[BUF_SIZE]; long nread; struct linux_dirent *d; fd = open(argc > 1 ? argv[1] : ".", O_RDONLY | O_DIRECTORY); if (fd == -1) err(EXIT_FAILURE, "open"); for (;;) { nread = syscall(SYS_getdents, fd, buf, BUF_SIZE); if (nread == -1) err(EXIT_FAILURE, "getdents"); if (nread == 0) break; printf("--------------- nread=%ld ---------------\n", nread); printf("inode# file type d_reclen d_off d_name\n"); for (size_t bpos = 0; bpos < nread;) { d = (struct linux_dirent *) (buf + bpos); printf("%8lu ", d->d_ino); d_type = *(buf + bpos + d->d_reclen - 1); printf("%-10s ", (d_type == DT_REG) ? "regular" : (d_type == DT_DIR) ? "directory" : (d_type == DT_FIFO) ? "FIFO" : (d_type == DT_SOCK) ? "socket" : (d_type == DT_LNK) ? "symlink" : (d_type == DT_BLK) ? "block dev" : (d_type == DT_CHR) ? "char dev" : "???"); printf("%4d %10jd %s\n", d->d_reclen, (intmax_t) d->d_off, d->d_name); bpos += d->d_reclen; } } exit(EXIT_SUCCESS); } ``` ## SEE ALSO [**readdir**(2)](/readdir/2.md), [**readdir**(3)](/readdir/3.md), [**inode**(7)](/inode/7.md)