ios_base::register_callback

指定回调函数。

void register_callback( 
   event_callback pfn, 
   int idx 
);

参数

• pfn
  对回调函数的指针。

• idx
  一个用户定义的数字。

备注

成员函数会将对 {pfn，以便存储的回调堆栈 回调堆栈上的 idx}。 在回调事件报告时，ev 函数。相反顺序，注册表调用，表达式由pfn(###*)，*this(ev、  idx)。

示例

// ios_base_register_callback.cpp
// compile with: /EHsc
#include <iostream>
#include <fstream>

using namespace std;

void callback1( ios_base::event e, ios_base& stream, int arg ) 
{
   cout << "in callback1" << endl;
   switch ( e ) 
   {
      case ios_base::erase_event:
         cout << "an erase event" << endl;
         break;
      case ios_base::imbue_event:
         cout << "an imbue event" << endl;
         break;
      case ios_base::copyfmt_event:
         cout << "an copyfmt event" << endl;
         break;
   };
}

void callback2( ios_base::event e, ios_base& stream, int arg ) 
{
   cout << "in callback2" << endl;
   switch ( e ) 
   {
      case ios_base::erase_event:
         cout << "an erase event" << endl;
         break;
      case ios_base::imbue_event:
         cout << "an imbue event" << endl;
         break;
      case ios_base::copyfmt_event:
         cout << "an copyfmt event" << endl;
         break;
   };
}

int main( ) 
{
   // Make sure the imbue will not throw an exception
   // assert( setlocale( LC_ALL, "german" )!=NULL );

   cout.register_callback( callback1, 0 );
   cin.register_callback( callback2, 0 );

   try 
   {
      // If no exception because the locale's not found,
      // generate an imbue_event on callback1
      cout.imbue(locale("german"));
   }
   catch(...) 
   {
      cout << "exception" << endl;
   }

   // This will
   // (1) erase_event on callback1
   // (2) copyfmt_event on callback2
   cout.copyfmt(cin);

   // We get two erase events from callback2 at the end because 
// both cin and cout have callback2 registered when cin and cout
   // are destroyed at the end of program.
}

要求

页眉： <ios>

命名空间: std

请参见

参考

ios_base 类

iostream 编程

iostreams 约定