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authorAntonio Ospite <ospite@studenti.unina.it>2013-12-16 04:52:17 -0500
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2013-12-16 05:13:35 -0500
commitc2729850985934a3124319f8ff1d46d8c72bb012 (patch)
tree74238d313e0479e72341accd1176270f69ea6b0b /Documentation/input
parent7d0e6192c2f36139e4aa5e4107f4d7fb56d9f290 (diff)
Input: joystick - use sizeof(VARIABLE) in documentation
Use the preferred style sizeof(VARIABLE) instead of sizeof(TYPE) in the joystick API documentation, Documentation/CodingStyle states that this is the preferred style for allocations but using it elsewhere is good too. Also fix some errors like "sizeof(struct mybuffer)" which didn't mean anything. Signed-off-by: Antonio Ospite <ospite@studenti.unina.it> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to 'Documentation/input')
-rw-r--r--Documentation/input/joystick-api.txt36
1 files changed, 18 insertions, 18 deletions
diff --git a/Documentation/input/joystick-api.txt b/Documentation/input/joystick-api.txt
index f95f64838788..943b18eac918 100644
--- a/Documentation/input/joystick-api.txt
+++ b/Documentation/input/joystick-api.txt
@@ -23,7 +23,7 @@ By default, the device is opened in blocking mode.
23~~~~~~~~~~~~~~~~ 23~~~~~~~~~~~~~~~~
24 24
25 struct js_event e; 25 struct js_event e;
26 read (fd, &e, sizeof(struct js_event)); 26 read (fd, &e, sizeof(e));
27 27
28where js_event is defined as 28where js_event is defined as
29 29
@@ -34,8 +34,8 @@ where js_event is defined as
34 __u8 number; /* axis/button number */ 34 __u8 number; /* axis/button number */
35 }; 35 };
36 36
37If the read is successful, it will return sizeof(struct js_event), unless 37If the read is successful, it will return sizeof(e), unless you wanted to read
38you wanted to read more than one event per read as described in section 3.1. 38more than one event per read as described in section 3.1.
39 39
40 40
412.1 js_event.type 412.1 js_event.type
@@ -99,9 +99,9 @@ may work well if you handle JS_EVENT_INIT events separately,
99 99
100 if ((js_event.type & ~JS_EVENT_INIT) == JS_EVENT_BUTTON) { 100 if ((js_event.type & ~JS_EVENT_INIT) == JS_EVENT_BUTTON) {
101 if (js_event.value) 101 if (js_event.value)
102 buttons_state |= (1 << js_event.number); 102 buttons_state |= (1 << js_event.number);
103 else 103 else
104 buttons_state &= ~(1 << js_event.number); 104 buttons_state &= ~(1 << js_event.number);
105 } 105 }
106 106
107is much safer since it can't lose sync with the driver. As you would 107is much safer since it can't lose sync with the driver. As you would
@@ -144,14 +144,14 @@ all events on the queue (that is, until you get a -1).
144For example, 144For example,
145 145
146 while (1) { 146 while (1) {
147 while (read (fd, &e, sizeof(struct js_event)) > 0) { 147 while (read (fd, &e, sizeof(e)) > 0) {
148 process_event (e); 148 process_event (e);
149 } 149 }
150 /* EAGAIN is returned when the queue is empty */ 150 /* EAGAIN is returned when the queue is empty */
151 if (errno != EAGAIN) { 151 if (errno != EAGAIN) {
152 /* error */ 152 /* error */
153 } 153 }
154 /* do something interesting with processed events */ 154 /* do something interesting with processed events */
155 } 155 }
156 156
157One reason for emptying the queue is that if it gets full you'll start 157One reason for emptying the queue is that if it gets full you'll start
@@ -181,7 +181,7 @@ at a time using the typical read(2) functionality. For that, you would
181replace the read above with something like 181replace the read above with something like
182 182
183 struct js_event mybuffer[0xff]; 183 struct js_event mybuffer[0xff];
184 int i = read (fd, mybuffer, sizeof(struct mybuffer)); 184 int i = read (fd, mybuffer, sizeof(mybuffer));
185 185
186In this case, read would return -1 if the queue was empty, or some 186In this case, read would return -1 if the queue was empty, or some
187other value in which the number of events read would be i / 187other value in which the number of events read would be i /
@@ -269,9 +269,9 @@ The driver offers backward compatibility, though. Here's a quick summary:
269 struct JS_DATA_TYPE js; 269 struct JS_DATA_TYPE js;
270 while (1) { 270 while (1) {
271 if (read (fd, &js, JS_RETURN) != JS_RETURN) { 271 if (read (fd, &js, JS_RETURN) != JS_RETURN) {
272 /* error */ 272 /* error */
273 } 273 }
274 usleep (1000); 274 usleep (1000);
275 } 275 }
276 276
277As you can figure out from the example, the read returns immediately, 277As you can figure out from the example, the read returns immediately,