<?xml version="1.0"?>
<rss version="2.0">
	<channel>
		<title>Keyboard Event Issue (aka: The Tales of a man who didn&#39;t knew how to code)</title>
		<link>http://www.allegro.cc/forums/view/617396</link>
		<description>Allegro.cc Forum Thread</description>
		<webMaster>matthew@allegro.cc (Matthew Leverton)</webMaster>
		<lastBuildDate>Sat, 12 May 2018 18:53:06 +0000</lastBuildDate>
	</channel>
	<item>
		<description><![CDATA[<div class="mockup v2"><p>Hello everybody !<br />I&#39;m having trouble using Allegro&#39;s Event system, and since i&#39;m quite new to programming i can&#39;t figure out what&#39;s going wrong...</p><p>I&#39;m trying to use a really simple test code:</p><div class="source-code"><div class="toolbar"><span class="button numbers"><b>#</b></span><span class="button select">Select</span><span class="button expand">Expand</span></div><div class="inner"><span class="number">  1</span><span class="p">#include &lt;iostream&gt;</span>
<span class="number">  2</span><span class="p">#include "allegro5/allegro.h"</span>
<span class="number">  3</span>
<span class="number">  4</span><span class="k1">int</span> main<span class="k2">(</span><span class="k1">int</span> argc, <span class="k1">char</span> <span class="k3">*</span><span class="k3">*</span>argv<span class="k2">)</span>
<span class="number">  5</span><span class="k2">{</span>
<span class="number">  6</span>    <a href="http://www.allegro.cc/manual/al_init"><span class="a">al_init</span></a><span class="k2">(</span><span class="k2">)</span><span class="k2">;</span>
<span class="number">  7</span>    <a href="http://www.allegro.cc/manual/ALLEGRO_DISPLAY"><span class="a">ALLEGRO_DISPLAY</span></a> <span class="k3">*</span> mainDisplay <span class="k3">=</span> <a href="http://www.allegro.cc/manual/al_create_display"><span class="a">al_create_display</span></a><span class="k2">(</span><span class="n">1200</span>,<span class="n">700</span><span class="k2">)</span><span class="k2">;</span>
<span class="number">  8</span>    <span class="k1">if</span><span class="k2">(</span><span class="k3">!</span><a href="http://www.allegro.cc/manual/al_install_keyboard"><span class="a">al_install_keyboard</span></a><span class="k2">(</span><span class="k2">)</span><span class="k2">)</span>
<span class="number">  9</span>    <span class="k2">{</span>
<span class="number"> 10</span>        cout <span class="k3">&lt;</span><span class="k3">&lt;</span> <span class="s">"Keyboard Installation Failed"</span><span class="k2">;</span>
<span class="number"> 11</span>        <span class="k1">return</span> <span class="n">1</span><span class="k2">;</span>
<span class="number"> 12</span>    <span class="k2">}</span>
<span class="number"> 13</span>    <a href="http://www.allegro.cc/manual/ALLEGRO_EVENT_SOURCE"><span class="a">ALLEGRO_EVENT_SOURCE</span></a> <span class="k3">*</span> keyboardEventSource <span class="k3">=</span> <a href="http://www.allegro.cc/manual/al_get_keyboard_event_source"><span class="a">al_get_keyboard_event_source</span></a><span class="k2">(</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 14</span>    <a href="http://www.allegro.cc/manual/ALLEGRO_EVENT_QUEUE"><span class="a">ALLEGRO_EVENT_QUEUE</span></a> <span class="k3">*</span> keyboardEventQueue <span class="k3">=</span> <a href="http://www.allegro.cc/manual/al_create_event_queue"><span class="a">al_create_event_queue</span></a><span class="k2">(</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 15</span>    <a href="http://www.allegro.cc/manual/ALLEGRO_EVENT"><span class="a">ALLEGRO_EVENT</span></a> <span class="k3">*</span> keyboardEvent<span class="k2">;</span>
<span class="number"> 16</span>    <a href="http://www.allegro.cc/manual/al_register_event_source"><span class="a">al_register_event_source</span></a><span class="k2">(</span>keyboardEventQueue,keyboardEventSource<span class="k2">)</span><span class="k2">;</span>
<span class="number"> 17</span>    <span class="k1">do</span>
<span class="number"> 18</span>    <span class="k2">{</span>
<span class="number"> 19</span>        <span class="k1">while</span> <span class="k2">(</span><span class="k3">!</span><a href="http://www.allegro.cc/manual/al_get_next_event"><span class="a">al_get_next_event</span></a><span class="k2">(</span>keyboardEventQueue,keyboardEvent<span class="k2">)</span><span class="k2">)</span>
<span class="number"> 20</span>        <span class="k2">{</span>
<span class="number"> 21</span>        <span class="k2">}</span> <span class="c">//I know this while loop is ugly, but thats just a test code OK ? ;)</span>
<span class="number"> 22</span>        <span class="c">//It crashes here (when i press a key down)... :-/</span>
<span class="number"> 23</span>    <span class="k2">}</span><span class="k1">while</span> <span class="k2">(</span>keyboardEvent-&gt;type <span class="k3">!</span><span class="k3">=</span> ALLEGRO_EVENT_KEY_DOWN<span class="k2">)</span><span class="k2">;</span>
<span class="number"> 24</span>
<span class="number"> 25</span>    <span class="k1">int</span> <a href="http://www.allegro.cc/manual/key"><span class="a">key</span></a> <span class="k3">=</span> keyboardEvent-&gt;keyboard.keycode<span class="k2">;</span>
<span class="number"> 26</span>    cout <span class="k3">&lt;</span><span class="k3">&lt;</span> <a href="http://www.allegro.cc/manual/key"><span class="a">key</span></a><span class="k2">;</span>
<span class="number"> 27</span>    <span class="k1">return</span> <span class="n">0</span><span class="k2">;</span>
<span class="number"> 28</span><span class="k2">}</span>
</div></div><p>

Everything works fine, until i press a key, then my program crashes with this error code: 0xC0000005    (no more comments)</p><p>Where did I make a mistake ? <img src="http://www.allegro.cc/forums/smileys/sad.gif" alt=":(" /></p><p>Thanks for your help ! <img src="http://www.allegro.cc/forums/smileys/cheesy.gif" alt=":D" /></p><p>PS: I&#39;m on Win10 and i&#39;m using C::B
</p></div>]]>
		</description>
		<author>no-reply@allegro.cc (mumu1000)</author>
		<pubDate>Sun, 29 Apr 2018 23:52:03 +0000</pubDate>
	</item>
	<item>
		<description><![CDATA[<div class="mockup v2"><div class="quote_container"><div class="title"><a href="http://www.allegro.cc/forums/thread/617396/1037131#target">mumu1000</a> said:</div><div class="quote"><p>
</p><div class="source-code snippet"><div class="inner"><pre> <a href="http://www.allegro.cc/manual/ALLEGRO_EVENT"><span class="a">ALLEGRO_EVENT</span></a> <span class="k3">*</span> keyboardEvent<span class="k2">;</span>
</pre></div></div><p>
</p></div></div><p>
That should be an ALLEGRO_EVENT, not an ALLEGRO_EVENT*. A pointer is an address, and in this case you didn&#39;t initialize the value either. So when al_wait_for_event returns and tries to fill in the data at the address of the ALLEGRO_EVENT you passed into it, it crashes, with an access violation.
</p></div>]]>
		</description>
		<author>no-reply@allegro.cc (Edgar Reynaldo)</author>
		<pubDate>Mon, 30 Apr 2018 00:10:18 +0000</pubDate>
	</item>
	<item>
		<description><![CDATA[<div class="mockup v2"><p>Thank you alot (again ;p )</p><p>I think it will solve my problem ! <img src="http://www.allegro.cc/forums/smileys/cheesy.gif" alt=":D" />
</p></div>]]>
		</description>
		<author>no-reply@allegro.cc (mumu1000)</author>
		<pubDate>Mon, 30 Apr 2018 03:07:20 +0000</pubDate>
	</item>
	<item>
		<description><![CDATA[<div class="mockup v2"><p>That should fix it.</p><p>Bump if you have questions.
</p></div>]]>
		</description>
		<author>no-reply@allegro.cc (Edgar Reynaldo)</author>
		<pubDate>Mon, 30 Apr 2018 11:02:06 +0000</pubDate>
	</item>
	<item>
		<description><![CDATA[<div class="mockup v2"><div class="source-code snippet"><div class="inner"><pre><a href="http://www.allegro.cc/manual/ALLEGRO_EVENT"><span class="a">ALLEGRO_EVENT</span></a> keyboardEvent<span class="k2">;</span>

...

<span class="c">// also change this to pass the address of the event object</span>
</pre></div></div><p><s>while (!al_get_next_event(keyboardEventQueue, @keyboardEvent))</s></p><div class="source-code snippet"><div class="inner"><pre><span class="k1">while</span> <span class="k2">(</span><span class="k3">!</span><a href="http://www.allegro.cc/manual/al_get_next_event"><span class="a">al_get_next_event</span></a><span class="k2">(</span>keyboardEventQueue, <span class="k3">&amp;</span>keyboardEvent<span class="k2">)</span><span class="k2">)</span>
</pre></div></div><p>
</p></div>]]>
		</description>
		<author>no-reply@allegro.cc (DanielH)</author>
		<pubDate>Wed, 02 May 2018 21:01:30 +0000</pubDate>
	</item>
	<item>
		<description><![CDATA[<div class="mockup v2"><div class="quote_container"><div class="title"><a href="https://www.allegro.cc/forums/thread/617396/1037201#target">DanielH</a> said:</div><div class="quote"><p><span class="source-code"><span class="k3">&amp;</span>keyboardEvent</span></p></div></div><p>

FTFY. The address-of (&#39;&amp;&#39;) operator in C returns the address of its operand.
</p></div>]]>
		</description>
		<author>no-reply@allegro.cc (bamccaig)</author>
		<pubDate>Wed, 02 May 2018 23:27:52 +0000</pubDate>
	</item>
	<item>
		<description><![CDATA[<div class="mockup v2"><p>Looks like DanielH is using Pascal or some other Wirth-lesque language. <img src="http://www.allegro.cc/forums/smileys/wink.gif" alt=";)" />
</p></div>]]>
		</description>
		<author>no-reply@allegro.cc (Niunio)</author>
		<pubDate>Mon, 07 May 2018 14:44:52 +0000</pubDate>
	</item>
	<item>
		<description><![CDATA[<div class="mockup v2"><p>Thanks alot for your replies !<br />I shall ask you if I have any questions ! (I will definitely have some later ;p)
</p></div>]]>
		</description>
		<author>no-reply@allegro.cc (mumu1000)</author>
		<pubDate>Sat, 12 May 2018 18:53:06 +0000</pubDate>
	</item>
</rss>
