Revision Difference
Global.xpcall#511387
<function name="xpcall" parent="Global" type="libraryfunc">⤶
<description>⤶
Attempts to call the first function. If the execution succeeds, this returns `true` followed by the returns of the function. If execution fails, this returns `false` and the second function is called with the error message. ⤶
⤶
Unlike in <page>Global.pcall</page>, the stack is not unwound and can therefore be used for stack analyses with the <page>debug</page>.⤶
⤶
<bug issue="1976">Using this function with <page>Global.include</page> will break autorefresh.</bug>⤶
⤶
<bug issue="2036">This cannot stop errors from hooks called from the engine.</bug>⤶
⤶
<bug issue="2498">This does not stop <page>Global.Error</page> and <page>Global.ErrorNoHalt</page> from sending error messages to the server (if called clientside) or calling the <page>GM:OnLuaError</page> hook. The success boolean returned will always return true and thus you will not get the error message returned. <page>Global.error</page> does not exhibit these behaviours.</bug>⤶
⤶
<bug issue="3112">This does not stop errors incurred by <page>Global.include</page>.</bug>⤶
</description>⤶
<realm>Shared and Menu</realm>⤶
<args>⤶
<arg name="func" type="function">The function to call initially.</arg>⤶
<arg name="errorCallback" type="function">The function to be called if execution of the first fails; the error message is passed as a string.

You cannot throw an <page>Global.error</page>() from this callback: it will have no effect (not even stopping the callback).</arg>⤶
<arg name="arguments" type="vararg">Arguments to pass to the initial function.</arg>⤶
</args>⤶
<rets>⤶
<ret name="" type="boolean">Status of the execution; `true` for success, `false` for failure.</ret>⤶
<ret name="" type="vararg">The returns of the first function if execution succeeded, otherwise the **first** return value of the error callback.</ret>⤶
</rets>⤶
</function>⤶
⤶
<example>⤶
<description>Using xpcall to catch an error.</description>⤶
<code>⤶
local function test()⤶
aisj()⤶
end⤶
⤶
local function catch( err )⤶
print( "ERROR: ", err )⤶
end⤶
⤶
print( "Output: ", xpcall( test, catch ) )⤶
</code>⤶
<output>⤶
⤶
```⤶
ERROR: &#09;lua/wiki/xpcall_example.lua:2: attempt to call global 'aisj' (a nil value)⤶
Output:&#09;false &#09;nil⤶
```⤶
⤶
</output>⤶
⤶
</example>
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