projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 8e080c2e MCC |
1 | <refentry id="func-munmap"> |
| 2 | <refmeta> | |
| 3 | <refentrytitle>V4L2 munmap()</refentrytitle> | |
| 4 | &manvol; | |
| 5 | </refmeta> | |
| 6 | ||
| 7 | <refnamediv> | |
| 8 | <refname>v4l2-munmap</refname> | |
| 9 | <refpurpose>Unmap device memory</refpurpose> | |
| 10 | </refnamediv> | |
| 11 | ||
| 12 | <refsynopsisdiv> | |
| 13 | <funcsynopsis> | |
| 14 | <funcsynopsisinfo> | |
| 15 | #include <unistd.h> | |
| 16 | #include <sys/mman.h></funcsynopsisinfo> | |
| 17 | <funcprototype> | |
| 18 | <funcdef>int <function>munmap</function></funcdef> | |
| 19 | <paramdef>void *<parameter>start</parameter></paramdef> | |
| 20 | <paramdef>size_t <parameter>length</parameter></paramdef> | |
| 21 | </funcprototype> | |
| 22 | </funcsynopsis> | |
| 23 | </refsynopsisdiv> | |
| 24 | <refsect1> | |
| 25 | <title>Arguments</title> | |
| 26 | <variablelist> | |
| 27 | <varlistentry> | |
| 28 | <term><parameter>start</parameter></term> | |
| 29 | <listitem> | |
| 30 | <para>Address of the mapped buffer as returned by the | |
| 31 | &func-mmap; function.</para> | |
| 32 | </listitem> | |
| 33 | </varlistentry> | |
| 34 | <varlistentry> | |
| 35 | <term><parameter>length</parameter></term> | |
| 36 | <listitem> | |
| 37 | <para>Length of the mapped buffer. This must be the same | |
| 38 | value as given to <function>mmap()</function> and returned by the | |
| 39 | driver in the &v4l2-buffer; <structfield>length</structfield> | |
| 53b5d574 PO |
40 | field for the single-planar API and in the &v4l2-plane; |
| 41 | <structfield>length</structfield> field for the multi-planar API.</para> | |
| 8e080c2e MCC |
42 | </listitem> |
| 43 | </varlistentry> | |
| 44 | </variablelist> | |
| 45 | </refsect1> | |
| 46 | ||
| 47 | <refsect1> | |
| 48 | <title>Description</title> | |
| 49 | ||
| 50 | <para>Unmaps a previously with the &func-mmap; function mapped | |
| 51 | buffer and frees it, if possible. <!-- ? This function (not freeing) | |
| 52 | has no impact on I/O in progress, specifically it does not imply | |
| 53 | &VIDIOC-STREAMOFF; to terminate I/O. Unmapped buffers can still be | |
| 54 | enqueued, dequeued or queried, they are just not accessible by the | |
| 55 | application.--></para> | |
| 56 | </refsect1> | |
| 57 | ||
| 58 | <refsect1> | |
| 59 | <title>Return Value</title> | |
| 60 | ||
| 61 | <para>On success <function>munmap()</function> returns 0, on | |
| 62 | failure -1 and the <varname>errno</varname> variable is set | |
| 63 | appropriately:</para> | |
| 64 | ||
| 65 | <variablelist> | |
| 66 | <varlistentry> | |
| 67 | <term><errorcode>EINVAL</errorcode></term> | |
| 68 | <listitem> | |
| 69 | <para>The <parameter>start</parameter> or | |
| 70 | <parameter>length</parameter> is incorrect, or no buffers have been | |
| 71 | mapped yet.</para> | |
| 72 | </listitem> | |
| 73 | </varlistentry> | |
| 74 | </variablelist> | |
| 75 | </refsect1> | |
| 76 | </refentry> |