1 | /* |
2 | # (C) 2008 Hans de Goede <hdegoede@redhat.com> |
3 | |
4 | # This program is free software; you can redistribute it and/or modify |
5 | # it under the terms of the GNU Lesser General Public License as published by |
6 | # the Free Software Foundation; either version 2.1 of the License, or |
7 | # (at your option) any later version. |
8 | # |
9 | # This program is distributed in the hope that it will be useful, |
10 | # but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
12 | # GNU Lesser General Public License for more details. |
13 | # |
14 | # You should have received a copy of the GNU Lesser General Public License |
15 | # along with this program; if not, write to the Free Software |
16 | # Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA |
17 | */ |
18 | |
19 | #ifndef __LIBV4L2_H |
20 | #define __LIBV4L2_H |
21 | |
22 | #include <stdio.h> |
23 | #include <unistd.h> |
24 | #include <stdint.h> |
25 | |
26 | #ifdef __cplusplus |
27 | extern "C" { |
28 | #endif /* __cplusplus */ |
29 | |
30 | #if HAVE_VISIBILITY |
31 | #define LIBV4L_PUBLIC __attribute__ ((visibility("default"))) |
32 | #else |
33 | #define LIBV4L_PUBLIC |
34 | #endif |
35 | |
36 | /* Point this to a FILE opened for writing when you want to log error and |
37 | status messages to a file, when NULL errors will get send to stderr */ |
38 | LIBV4L_PUBLIC extern FILE *v4l2_log_file; |
39 | |
40 | /* Just like your regular open/close/etc, except that format conversion is |
41 | done if necessary when capturing. That is if you (try to) set a capture |
42 | format which is not supported by the cam, but is supported by libv4lconvert, |
43 | then the try_fmt / set_fmt will succeed as if the cam supports the format |
44 | and on dqbuf / read the data will be converted for you and returned in |
45 | the request format. enum_fmt will also report support for the formats to |
46 | which conversion is possible. |
47 | |
48 | Another difference is that you can make v4l2_read() calls even on devices |
49 | which do not support the regular read() method. |
50 | |
51 | Note the device name passed to v4l2_open must be of a video4linux2 device, |
52 | if it is anything else (including a video4linux1 device), v4l2_open will |
53 | fail. |
54 | |
55 | Note that the argument to v4l2_ioctl after the request must be a valid |
56 | memory address of structure of the appropriate type for the request (for |
57 | v4l2 requests which expect a structure address). Passing in NULL or an |
58 | invalid memory address will not lead to failure with errno being EFAULT, |
59 | as it would with a real ioctl, but will cause libv4l2 to break, and you |
60 | get to keep both pieces. |
61 | */ |
62 | |
63 | LIBV4L_PUBLIC int v4l2_open(const char *file, int oflag, ...); |
64 | LIBV4L_PUBLIC int v4l2_close(int fd); |
65 | LIBV4L_PUBLIC int v4l2_dup(int fd); |
66 | LIBV4L_PUBLIC int v4l2_ioctl(int fd, unsigned long int request, ...); |
67 | LIBV4L_PUBLIC ssize_t v4l2_read(int fd, void *buffer, size_t n); |
68 | LIBV4L_PUBLIC ssize_t v4l2_write(int fd, const void *buffer, size_t n); |
69 | LIBV4L_PUBLIC void *v4l2_mmap(void *start, size_t length, int prot, int flags, |
70 | int fd, int64_t offset); |
71 | LIBV4L_PUBLIC int v4l2_munmap(void *_start, size_t length); |
72 | |
73 | |
74 | /* Misc utility functions */ |
75 | |
76 | /* This function takes a value of 0 - 65535, and then scales that range to |
77 | the actual range of the given v4l control id, and then if the cid exists |
78 | and is not locked sets the cid to the scaled value. |
79 | |
80 | Normally returns 0, even if the cid did not exist or was locked, returns |
81 | non 0 when an other error occured. */ |
82 | LIBV4L_PUBLIC int v4l2_set_control(int fd, int cid, int value); |
83 | |
84 | /* This function returns a value of 0 - 65535, scaled to from the actual range |
85 | of the given v4l control id. When the cid does not exist, or could not be |
86 | accessed -1 is returned. */ |
87 | LIBV4L_PUBLIC int v4l2_get_control(int fd, int cid); |
88 | |
89 | |
90 | /* "low level" access functions, these functions allow somewhat lower level |
91 | access to libv4l2 (currently there only is v4l2_fd_open here) */ |
92 | |
93 | /* Flags for v4l2_fd_open's v4l2_flags argument */ |
94 | |
95 | /* Disable all format conversion done by libv4l2, this includes the software |
96 | whitebalance, gamma correction, flipping, etc. libv4lconvert does. Use this |
97 | if you want raw frame data, but still want the additional error checks and |
98 | the read() emulation libv4l2 offers. */ |
99 | #define V4L2_DISABLE_CONVERSION 0x01 |
100 | /* This flag is *OBSOLETE*, since version 0.5.98 libv4l *always* reports |
101 | emulated formats to ENUM_FMT, except when conversion is disabled. */ |
102 | #define V4L2_ENABLE_ENUM_FMT_EMULATION 0x02 |
103 | |
104 | /* v4l2_fd_open: open an already opened fd for further use through |
105 | v4l2lib and possibly modify libv4l2's default behavior through the |
106 | v4l2_flags argument. |
107 | |
108 | Returns fd on success, -1 if the fd is not suitable for use through libv4l2 |
109 | (note the fd is left open in this case). */ |
110 | LIBV4L_PUBLIC int v4l2_fd_open(int fd, int v4l2_flags); |
111 | |
112 | #ifdef __cplusplus |
113 | } |
114 | #endif /* __cplusplus */ |
115 | |
116 | #endif |
117 | |