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<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
<div class="doc_text">
+
<h5>Overview:</h5>
+
<p>The function type can be thought of as a function signature. It
consists of a return type and a list of formal parameter types. The
-return type of a function type is a scalar type or a void type or a struct type.
+return type of a function type is a scalar type, a void type, or a struct type.
If the return type is a struct type then all struct elements must be of first
-class types. Function types are usually used to build virtual function tables
-(which are structures of pointers to functions), for indirect function
-calls, and when defining a function.</p>
+class types, and the struct must have at least one element.</p>
<h5>Syntax:</h5>
-<pre> <returntype list> (<parameter list>)<br></pre>
+
+<pre>
+ <returntype list> (<parameter list>)
+</pre>
+
<p>...where '<tt><parameter list></tt>' is a comma-separated list of type
specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
which indicates that the function takes a variable number of arguments.
href="#int_varargs">variable argument handling intrinsic</a> functions.
'<tt><returntype list></tt>' is a comma-separated list of
<a href="#t_firstclass">first class</a> type specifiers.</p>
+
<h5>Examples:</h5>
<table class="layout">
<tr class="layout">
ret void <i>; Return from void function</i>
ret <type> <value>, <type> <value> <i>; Return two values from a non-void function </i>
</pre>
+
<h5>Overview:</h5>
+
<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
value) from a function back to the caller.</p>
<p>There are two forms of the '<tt>ret</tt>' instruction: one that
-returns a value and then causes control flow, and one that just causes
+returns value(s) and then causes control flow, and one that just causes
control flow to occur.</p>
+
<h5>Arguments:</h5>
-<p>The '<tt>ret</tt>' instruction may return one or multiple values. The
-type of each return value must be a '<a href="#t_firstclass">first class</a>'
- type. Note that a function is not <a href="#wellformed">well formed</a>
-if there exists a '<tt>ret</tt>' instruction inside of the function that
-returns values that do not match the return type of the function.</p>
+
+<p>The '<tt>ret</tt>' instruction may return zero, one or multiple values.
+The type of each return value must be a '<a href="#t_firstclass">first
+class</a>' type. Note that a function is not <a href="#wellformed">well
+formed</a> if there exists a '<tt>ret</tt>' instruction inside of the
+function that returns values that do not match the return type of the
+function.</p>
+
<h5>Semantics:</h5>
+
<p>When the '<tt>ret</tt>' instruction is executed, control flow
returns back to the calling function's context. If the caller is a "<a
href="#i_call"><tt>call</tt></a>" instruction, execution continues at
return value. If the instruction returns multiple values then these
values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
</a>' instruction.</p>
+
<h5>Example:</h5>
-<pre> ret i32 5 <i>; Return an integer value of 5</i>
+
+<pre>
+ ret i32 5 <i>; Return an integer value of 5</i>
ret void <i>; Return from a void function</i>
ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
</pre>