dirfd - get directory stream file descriptor
#include <sys/types.h> #include <dirent.h> int dirfd(DIR *dirp); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): dirfd(): /* Since glibc 2.10: */ _POSIX_C_SOURCE >= 200809L || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
The function dirfd() returns the file descriptor associated with the directory stream dirp. 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 fstat(2) and fchdir(2). It will be automatically closed when closedir(3) is called.
On success, a nonnegative file descriptor is returned. On error, -1 is returned, and errno is set to indicate the cause of the error.
POSIX.1-2008 specifies two errors, neither of which is returned by the current implementation. EINVAL dirp does not refer to a valid directory stream. ENOTSUP The implementation does not support the association of a file descriptor with a directory.
For an explanation of the terms used in this section, see attributes(7). Interface Attribute Value dirfd() Thread safety MT-Safe
POSIX.1-2008. This function was a BSD extension, present in 4.3BSD- Reno, not in 4.2BSD.
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