.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later .. c:namespace:: V4L .. _func-munmap: ************* V4L2 munmap() ************* Name ==== v4l2-munmap - Unmap device memory Synopsis ======== .. code-block:: c #include #include .. c:function:: int munmap( void *start, size_t length ) Arguments ========= ``start`` Address of the mapped buffer as returned by the :c:func:`mmap()` function. ``length`` Length of the mapped buffer. This must be the same value as given to :c:func:`mmap()` and returned by the driver in the struct :c:type:`v4l2_buffer` ``length`` field for the single-planar API and in the struct :c:type:`v4l2_plane` ``length`` field for the multi-planar API. Description =========== Unmaps a previously with the :c:func:`mmap()` function mapped buffer and frees it, if possible. Return Value ============ On success :c:func:`munmap()` returns 0, on failure -1 and the ``errno`` variable is set appropriately: EINVAL The ``start`` or ``length`` is incorrect, or no buffers have been mapped yet.