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Diffstat (limited to 'Documentation/media/uapi/v4l/func-write.rst')
| -rw-r--r-- | Documentation/media/uapi/v4l/func-write.rst | 91 |
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diff --git a/Documentation/media/uapi/v4l/func-write.rst b/Documentation/media/uapi/v4l/func-write.rst deleted file mode 100644 index 865129c726ad..000000000000 --- a/Documentation/media/uapi/v4l/func-write.rst +++ /dev/null @@ -1,91 +0,0 @@ -.. Permission is granted to copy, distribute and/or modify this -.. document under the terms of the GNU Free Documentation License, -.. Version 1.1 or any later version published by the Free Software -.. Foundation, with no Invariant Sections, no Front-Cover Texts -.. and no Back-Cover Texts. A copy of the license is included at -.. Documentation/media/uapi/fdl-appendix.rst. -.. -.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections - -.. _func-write: - -************ -V4L2 write() -************ - -Name -==== - -v4l2-write - Write to a V4L2 device - - -Synopsis -======== - -.. code-block:: c - - #include <unistd.h> - - -.. c:function:: ssize_t write( int fd, void *buf, size_t count ) - :name: v4l2-write - -Arguments -========= - -``fd`` - File descriptor returned by :ref:`open() <func-open>`. - -``buf`` - Buffer with data to be written - -``count`` - Number of bytes at the buffer - -Description -=========== - -:ref:`write() <func-write>` writes up to ``count`` bytes to the device -referenced by the file descriptor ``fd`` from the buffer starting at -``buf``. When the hardware outputs are not active yet, this function -enables them. When ``count`` is zero, :ref:`write() <func-write>` returns 0 -without any other effect. - -When the application does not provide more data in time, the previous -video frame, raw VBI image, sliced VPS or WSS data is displayed again. -Sliced Teletext or Closed Caption data is not repeated, the driver -inserts a blank line instead. - - -Return Value -============ - -On success, the number of bytes written are returned. Zero indicates -nothing was written. On error, -1 is returned, and the ``errno`` -variable is set appropriately. In this case the next write will start at -the beginning of a new frame. Possible error codes are: - -EAGAIN - Non-blocking I/O has been selected using the - :ref:`O_NONBLOCK <func-open>` flag and no buffer space was - available to write the data immediately. - -EBADF - ``fd`` is not a valid file descriptor or is not open for writing. - -EBUSY - The driver does not support multiple write streams and the device is - already in use. - -EFAULT - ``buf`` references an inaccessible memory area. - -EINTR - The call was interrupted by a signal before any data was written. - -EIO - I/O error. This indicates some hardware problem. - -EINVAL - The :ref:`write() <func-write>` function is not supported by this driver, - not on this device, or generally not on this type of device. |