| .\" Copyright (C) 2002 Andries Brouwer (aeb@cwi.nl) |
| .\" |
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| .TH DIRFD 3 2020-04-11 "Linux" "Linux Programmer's Manual" |
| .SH NAME |
| dirfd \- get directory stream file descriptor |
| .SH SYNOPSIS |
| .B #include <sys/types.h> |
| .br |
| .B #include <dirent.h> |
| .PP |
| .BI "int dirfd(DIR *" dirp ); |
| .PP |
| .in -4n |
| Feature Test Macro Requirements for glibc (see |
| .BR feature_test_macros (7)): |
| .in |
| .PP |
| .BR dirfd (): |
| .br |
| .RS 4 |
| .PD 0 |
| .ad l |
| /* Since glibc 2.10: */ _POSIX_C_SOURCE\ >=\ 200809L |
| || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE |
| .PD |
| .RE |
| .ad |
| .SH DESCRIPTION |
| The function |
| .BR dirfd () |
| returns the file descriptor associated with the directory stream |
| .IR dirp . |
| .PP |
| This file descriptor is the one used internally by the directory stream. |
| As a result, it is useful only for functions which do not depend on |
| or alter the file position, such as |
| .BR fstat (2) |
| and |
| .BR fchdir (2). |
| It will be automatically closed when |
| .BR closedir (3) |
| is called. |
| .SH RETURN VALUE |
| On success, |
| .BR dirfd () |
| returns a file descriptor (a nonnegative integer). |
| On error, \-1 is returned, and |
| .I errno |
| is set to indicate the cause of the error. |
| .SH ERRORS |
| POSIX.1-2008 specifies two errors, |
| neither of which is returned by the current |
| .\" glibc 2.8 |
| implementation. |
| .TP |
| .B EINVAL |
| .I dirp |
| does not refer to a valid directory stream. |
| .TP |
| .B ENOTSUP |
| The implementation does not support the association of a file |
| descriptor with a directory. |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .TS |
| allbox; |
| lb lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR dirfd () |
| T} Thread safety MT-Safe |
| .TE |
| .SH CONFORMING TO |
| POSIX.1-2008. |
| This function was a BSD extension, present in 4.3BSD-Reno, not in 4.2BSD. |
| .\" It is present in libc5 (since 5.1.2) and in glibc2. |
| .SH SEE ALSO |
| .BR open (2), |
| .BR openat (2), |
| .BR closedir (3), |
| .BR opendir (3), |
| .BR readdir (3), |
| .BR rewinddir (3), |
| .BR scandir (3), |
| .BR seekdir (3), |
| .BR telldir (3) |
