File descriptors

Collaboration diagram for File descriptors:

Functions
int	vlc_open (const char *filename, int flags,...)
	Opens a system file handle.
int	vlc_openat (int dir, const char *filename, int flags,...)
	Opens a system file handle relative to an existing directory handle.
int	vlc_mkstemp (char *)
int	vlc_dup (int oldfd)
	Duplicates a file descriptor.
int	vlc_dup2 (int oldfd, int newfd)
	Replaces a file descriptor.
int	vlc_pipe (int[2])
	Creates a pipe (see "man pipe" for further reference).
int	vlc_memfd (void)
	Creates an anonymous regular file descriptor, i.e.
ssize_t	vlc_write (int, const void *, size_t)
	Writes data to a file descriptor.
ssize_t	vlc_writev (int, const struct iovec *, int)
	Writes data from an iovec structure to a file descriptor.
int	vlc_close (int fd)
	Closes a file descriptor.

Detailed Description

Function Documentation

vlc_close()

int vlc_close

(

int

fd

)

Closes a file descriptor.

This closes a file descriptor. If this is a last file descriptor for the underlying open file, the file is closed too; the exact semantics depend on the type of file.

Note

The file descriptor is always closed when the function returns, even if the function returns an error. The sole exception is if the file descriptor was not currently valid, and thus cannot be closed (errno will then be set to EBADF).

Parameters

fd	file descriptor

Returns

Normally, zero is returned. If an I/O error is detected before or while closing, the function may return -1. Such an error is unrecoverable since the descriptor is closed.

A nul return value does not necessarily imply that all pending I/O succeeded, since I/O might still occur asynchronously afterwards.

vlc_dup()

int vlc_dup

(

int

oldfd

)

Duplicates a file descriptor.

Parameters

oldfd

file descriptor to duplicate

Note

Contrary to standard dup(), the new file descriptor has the close-on-exec descriptor flag preset.

Returns

a new file descriptor, -1 (see errno)

References likely.

Referenced by vlc_memfd().

vlc_dup2()

int vlc_dup2	(	int	oldfd,
		int	newfd
	)

Replaces a file descriptor.

This function duplicates a file descriptor to a specified file descriptor. This is primarily used to atomically replace a described file.

Parameters

oldfd	source file descriptor to copy
newfd	destination file descriptor to replace

Note

Contrary to standard dup2(), the new file descriptor has the close-on-exec descriptor flag preset.

Return values

newfd	success
-1	failure (see errno)

References vlc_cloexec().

vlc_memfd()

int vlc_memfd

(

void

)

Creates an anonymous regular file descriptor, i.e.

a descriptor for a temporary file.

The file is initially empty. The storage space is automatically reclaimed when all file descriptors referencing it are closed.

The new file descriptor has the close-on-exec flag preset.

Returns

a file descriptor on success, -1 on error (see errno)

References vlc_dup(), and vlc_mkstemp().

Referenced by picture_Allocate().

vlc_mkstemp()

int vlc_mkstemp

(

char *

template

)

References ARRAY_SIZE, vlc_open(), and vlc_rand_bytes().

Referenced by GetTmpFile(), and vlc_memfd().

vlc_open()

int vlc_open	(	const char *	filename,
		int	flags,
			...
	)

Opens a system file handle.

Parameters

filename	file path to open (with UTF-8 encoding)
flags	open() flags, see the C library open() documentation

Returns

a file handle on success, -1 on error (see errno).

Note

Contrary to standard open(), this function returns a file handle with the close-on-exec flag preset.

References ToLocaleDup, unlikely, and widen_path().

Referenced by config_SaveConfigFile(), vlc_fopen(), vlc_frame_FilePath(), vlc_mkstemp(), vlc_rand_init(), and WriteToFile().

vlc_openat()

int vlc_openat	(	int	dir,
		const char *	filename,
		int	flags,
			...
	)

Opens a system file handle relative to an existing directory handle.

Parameters

dir	directory file descriptor
filename	file path to open (with UTF-8 encoding)
flags	open() flags, see the C library open() documentation

Returns

a file handle on success, -1 on error (see errno).

Note

Contrary to standard open(), this function returns a file handle with the close-on-exec flag preset.

vlc_pipe()

int vlc_pipe

(

int

fds[2]

)

Creates a pipe (see "man pipe" for further reference).

The new file descriptors have the close-on-exec flag preset.

Returns

0 on success, -1 on error (see errno)

References vlc_cloexec(), and vlc_socketpair().

Referenced by vlc_getProxyUrl(), and vlc_poll_i11e_inner().

vlc_write()

ssize_t vlc_write	(	int	fd,
		const void *	buf,
		size_t	len
	)

Writes data to a file descriptor.

Unlike write(), if EPIPE error occurs, this function does not generate a SIGPIPE signal.

Note

If the file descriptor is known to be neither a pipe/FIFO nor a connection-oriented socket, the normal write() should be used.

References vlc_writev().

vlc_writev()

ssize_t vlc_writev	(	int	fd,
		const struct iovec *	iov,
		int	count
	)

Writes data from an iovec structure to a file descriptor.

Unlike writev(), if EPIPE error occurs, this function does not generate a SIGPIPE signal.

References count, and writev().

Referenced by vlc_write(), and vlc_writev_i11e().