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<div class="title">Good practices </div> </div>
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<div class="textblock"><p>This article will try to explain some good practices, that will help you get going faster and easier find the solution when a problem occurs.</p>
<h1><a class="anchor" id="doc_checkretval"></a>
Always check return values for registrations</h1>
<p>When configuring the script engine you should always check the return values, at least in debug mode. All error codes are negative so a simple <code>assert( r &gt;= 0 )</code> where r is the returned value is sufficient to pinpoint where the configuration failed.</p>
<p>If a function failed during the configuration, the <a class="el" href="classas_i_script_module.html#a8acf107194c5f079d7f7507309ebe613">Build</a> method will always fail with a return code of <a class="el" href="angelscript_8h.html#a6e2a1647f02f2c5da931bab09e860f54a7416ebaf18f32e180595fb366a072754">asINVALID_CONFIGURATION</a>. Unless you already verified the error codes for all the configuration calls, it will not be possible to determine what the error was.</p>
<div class="fragment"><div class="line"><span class="comment">// Verifying the return code with an assert is simple and won&#39;t pollute the code</span></div>
<div class="line">r = engine-&gt;<a class="code" href="classas_i_script_engine.html#a2f84b9b51733f22c68b8448b02c2f1c7">RegisterGlobalFunction</a>(<span class="stringliteral">&quot;void func()&quot;</span>, <a class="code" href="angelscript_8h.html#a78f8f2c7f1c88b12e74a5ac47b4184ae">asFUNCTION</a>(func), <a class="code" href="angelscript_8h.html#a3ec92ea3c4762e44c2df788ceccdd1e4a68ae43cc91cdfc3fa4590c9e6164e4f4">asCALL_CDECL</a>); assert( r &gt;= 0 );</div>
</div><!-- fragment --><p><code>assert()</code> can safely be used with engine registrations, since the engine will set the internal state to invalid configuration if a function fails. Even in release mode the failure is discovered when a script is built.</p>
<h1><a class="anchor" id="doc_usemsgcallbck"></a>
Use the message callback to receive detailed error messages</h1>
<p>The return code from the register functions, <a class="el" href="classas_i_script_module.html#a8acf107194c5f079d7f7507309ebe613">Build</a>, and <a class="el" href="classas_i_script_module.html#a1258d7cfeed965f36ba312beeb49e81c">CompileFunction</a>, can only tell you that something was wrong, not what it was. To help identify the exact problem the message callback should be used. The script library will then send messages explaining the error or warning in clear text.</p>
<p>See <a class="el" href="doc_compile_script.html#doc_compile_script_msg">Message callback</a> for more information on the message callback.</p>
<h1><a class="anchor" id="doc_checkexceptions"></a>
Always verify return value after executing script function</h1>
<p>The VM can provide detailed information on any exception that occur in the script, for example in which function and line of code the problem occurred. It is also possible to enumerate the callstack and even the local variables.</p>
<p>See <a class="el" href="doc_call_script_func.html#doc_call_script_4">Exception handling</a> </p>
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<div class="ttc" id="aclassas_i_script_engine_html_a2f84b9b51733f22c68b8448b02c2f1c7"><div class="ttname"><a href="classas_i_script_engine.html#a2f84b9b51733f22c68b8448b02c2f1c7">asIScriptEngine::RegisterGlobalFunction</a></div><div class="ttdeci">virtual int RegisterGlobalFunction(const char *declaration, const asSFuncPtr &amp;funcPointer, asDWORD callConv, void *auxiliary=0)=0</div><div class="ttdoc">Registers a global function.</div></div>
<div class="ttc" id="aangelscript_8h_html_a78f8f2c7f1c88b12e74a5ac47b4184ae"><div class="ttname"><a href="angelscript_8h.html#a78f8f2c7f1c88b12e74a5ac47b4184ae">asFUNCTION</a></div><div class="ttdeci">#define asFUNCTION(f)</div><div class="ttdoc">Returns an asSFuncPtr representing the function specified by the name.</div><div class="ttdef"><b>Definition:</b> angelscript.h:675</div></div>
<div class="ttc" id="aangelscript_8h_html_a3ec92ea3c4762e44c2df788ceccdd1e4a68ae43cc91cdfc3fa4590c9e6164e4f4"><div class="ttname"><a href="angelscript_8h.html#a3ec92ea3c4762e44c2df788ceccdd1e4a68ae43cc91cdfc3fa4590c9e6164e4f4">asCALL_CDECL</a></div><div class="ttdeci">@ asCALL_CDECL</div><div class="ttdoc">A cdecl function.</div><div class="ttdef"><b>Definition:</b> angelscript.h:226</div></div>
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