5.5.5 挂钩函数(APR_IMPLEMENT_EXTERNAL_HOOK_BASE)
从宏的名字我们就可以大体看出该宏实际上是实现了具体的挂钩注册函数，如果将其展开后我们会更加一目了然。该宏的定义也是冗长的很，如下所示：
#define APR_IMPLEMENT_EXTERNAL_HOOK_BASE(ns,link,name) \
link##_DECLARE(void) ns##_hook_##name(ns##_HOOK_##name##_t *pf, \
const char * const *aszPre, const char * const *aszSucc,int nOrder) \
{ \
ns##_LINK_##name##_t *pHook; \
if(!_hooks.link_##name) \
{ \
_hooks.link_##name=apr_array_make(apr_hook_global_pool,1,sizeof(ns##_LINK_##name##_t)); \
apr_hook_sort_register(#name,&_hooks.link_##name); \
} \
pHook=apr_array_push(_hooks.link_##name); \
pHook->pFunc=pf; \
pHook->aszPredecessors=aszPre; \
pHook->aszSuccessors=aszSucc; \
pHook->nOrder=nOrder; \
pHook->szName=apr_hook_debug_current; \
if(apr_hook_debug_enabled) \
apr_hook_debug_show(#name,aszPre,aszSucc); \
} \
APR_IMPLEMENT_HOOK_GET_PROTO(ns,link,name) \
{ \
return _hooks.link_##name; \
}
对于post_config挂钩，我们该宏展开的结果如下：
AP_DECLARE(int) ap_hook_post_config(ap_HOOK_post_config_t *pf,
const char * const *aszPre,
const char * const *aszSucc,
int nOrder)
{
