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| Previous: <a href="Function-Basics.html#Function-Basics" accesskey="p" rel="prev">Function Basics</a>, Up: <a href="Functions.html#Functions" accesskey="u" rel="up">Functions</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p> |
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| <a name="Function-Properties-1"></a> |
| <h4 class="subsection">10.8.2 Function Properties</h4> |
| <a name="index-function-properties"></a> |
| <a name="index-statements"></a> |
| |
| <p>To determine the scope of a function, you can use the |
| <code>DECL_CONTEXT</code> macro. This macro will return the class |
| (either a <code>RECORD_TYPE</code> or a <code>UNION_TYPE</code>) or namespace (a |
| <code>NAMESPACE_DECL</code>) of which the function is a member. For a virtual |
| function, this macro returns the class in which the function was |
| actually defined, not the base class in which the virtual declaration |
| occurred. |
| </p> |
| <p>In C, the <code>DECL_CONTEXT</code> for a function maybe another function. |
| This representation indicates that the GNU nested function extension |
| is in use. For details on the semantics of nested functions, see the |
| GCC Manual. The nested function can refer to local variables in its |
| containing function. Such references are not explicitly marked in the |
| tree structure; back ends must look at the <code>DECL_CONTEXT</code> for the |
| referenced <code>VAR_DECL</code>. If the <code>DECL_CONTEXT</code> for the |
| referenced <code>VAR_DECL</code> is not the same as the function currently |
| being processed, and neither <code>DECL_EXTERNAL</code> nor |
| <code>TREE_STATIC</code> hold, then the reference is to a local variable in |
| a containing function, and the back end must take appropriate action. |
| </p> |
| <dl compact="compact"> |
| <dt><code>DECL_EXTERNAL</code> |
| <a name="index-DECL_005fEXTERNAL-1"></a> |
| </dt> |
| <dd><p>This predicate holds if the function is undefined. |
| </p> |
| </dd> |
| <dt><code>TREE_PUBLIC</code> |
| <a name="index-TREE_005fPUBLIC-1"></a> |
| </dt> |
| <dd><p>This predicate holds if the function has external linkage. |
| </p> |
| </dd> |
| <dt><code>TREE_STATIC</code> |
| <a name="index-TREE_005fSTATIC"></a> |
| </dt> |
| <dd><p>This predicate holds if the function has been defined. |
| </p> |
| </dd> |
| <dt><code>TREE_THIS_VOLATILE</code> |
| <a name="index-TREE_005fTHIS_005fVOLATILE"></a> |
| </dt> |
| <dd><p>This predicate holds if the function does not return normally. |
| </p> |
| </dd> |
| <dt><code>TREE_READONLY</code> |
| <a name="index-TREE_005fREADONLY"></a> |
| </dt> |
| <dd><p>This predicate holds if the function can only read its arguments. |
| </p> |
| </dd> |
| <dt><code>DECL_PURE_P</code> |
| <a name="index-DECL_005fPURE_005fP"></a> |
| </dt> |
| <dd><p>This predicate holds if the function can only read its arguments, but |
| may also read global memory. |
| </p> |
| </dd> |
| <dt><code>DECL_VIRTUAL_P</code> |
| <a name="index-DECL_005fVIRTUAL_005fP"></a> |
| </dt> |
| <dd><p>This predicate holds if the function is virtual. |
| </p> |
| </dd> |
| <dt><code>DECL_ARTIFICIAL</code> |
| <a name="index-DECL_005fARTIFICIAL-2"></a> |
| </dt> |
| <dd><p>This macro holds if the function was implicitly generated by the |
| compiler, rather than explicitly declared. In addition to implicitly |
| generated class member functions, this macro holds for the special |
| functions created to implement static initialization and destruction, to |
| compute run-time type information, and so forth. |
| </p> |
| </dd> |
| <dt><code>DECL_FUNCTION_SPECIFIC_TARGET</code> |
| <a name="index-DECL_005fFUNCTION_005fSPECIFIC_005fTARGET-1"></a> |
| </dt> |
| <dd><p>This macro returns a tree node that holds the target options that are |
| to be used to compile this particular function or <code>NULL_TREE</code> if |
| the function is to be compiled with the target options specified on |
| the command line. |
| </p> |
| </dd> |
| <dt><code>DECL_FUNCTION_SPECIFIC_OPTIMIZATION</code> |
| <a name="index-DECL_005fFUNCTION_005fSPECIFIC_005fOPTIMIZATION-1"></a> |
| </dt> |
| <dd><p>This macro returns a tree node that holds the optimization options |
| that are to be used to compile this particular function or |
| <code>NULL_TREE</code> if the function is to be compiled with the |
| optimization options specified on the command line. |
| </p> |
| </dd> |
| </dl> |
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