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  1. #include <iostream>
  2. #include <sstream>
  3. using namespace std;
  4.  
  5. void badFunc(std::stringstream& s)
  6. {
  7. 	int len = s.str().length();
  8. 	cout << "badFunc(in operator << )  : length = " << len << "    " << s.str().c_str() << endl;
  9. 	if ( 20 <= len)
  10. 	{
  11. 		cout << "   => exception!(over 20)" << endl;
  12. 		throw "operator <<";
  13. 	}
  14. }
  15.  
  16. void doSomething(std::stringstream& s)
  17. {
  18. 	int len = s.str().length();
  19. 	cout << "doSomething(in destructor)  :  length = " << len << "    " << s.str().c_str() << endl;
  20. 	if ( 15 <= len )
  21. 	{
  22. 		cout << "   => exception!(over 15)" << endl;
  23. 		throw "destructor";
  24. 	}
  25. }
  26.  
  27. class Temporary_t	{
  28. 	std::stringstream& sstr;	//not own resource
  29. 	bool safe;
  30. 	Temporary_t(std::stringstream& s) : sstr(s), safe(false)	{ sstr.str(""); }
  31. 	Temporary_t(const Temporary_t&);
  32. 	Temporary_t& operator =(const Temporary_t&);
  33. public:
  34. 	~Temporary_t() throw(int)	{ if ( safe )	doSomething(sstr);	}
  35. 	template<typename T> Temporary_t& operator << (const T& data)
  36. 		{	safe = false;	sstr << data;	badFunc(sstr);	safe = true;	return *this;	}
  37. 	friend Temporary_t temporary_t(std::stringstream& s);
  38. };
  39. Temporary_t temporary_t(std::stringstream& s)	{ return Temporary_t(s); }
  40.  
  41.  
  42. int main()
  43. {
  44. 	std::stringstream s;
  45. 	try	{
  46. 		temporary_t(s) << "ABCD " << 1234;
  47. 		throw "other";
  48. 	}
  49. 	catch (const char* e)	{	cout << "catch " << e << endl << endl;	}
  50. 	try	{
  51. 		temporary_t(s) << "ABCDEFGHIJ " << 1234567890;
  52. 		throw "other";
  53. 	}
  54. 	catch (const char* e)	{	cout << "catch " << e << endl << endl;	}
  55. 	try	{
  56. 		temporary_t(s) << "ABCDEFGHI " << 123456789;
  57. 		throw "other";
  58. 	}
  59. 	catch (const char* e)	{	cout << "catch " << e << endl;	}
  60. 	catch (...)				{	cout << "catch else";	}
  61. 	return 0;
  62. }
  63.  
  64.  
Runtime error #stdin #stdout #stderr 0s 3480KB
comments (?)
stdin
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Standard input is empty
stdout
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badFunc(in operator << )  : length = 5    ABCD 
badFunc(in operator << )  : length = 9    ABCD 1234
doSomething(in destructor)  :  length = 9    ABCD 1234
catch other

badFunc(in operator << )  : length = 11    ABCDEFGHIJ 
badFunc(in operator << )  : length = 21    ABCDEFGHIJ 1234567890
   => exception!(over 20)
catch operator <<

badFunc(in operator << )  : length = 10    ABCDEFGHI 
badFunc(in operator << )  : length = 19    ABCDEFGHI 123456789
doSomething(in destructor)  :  length = 19    ABCDEFGHI 123456789
   => exception!(over 15)
stderr
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terminate called after throwing an instance of 'char const*'
https://ideone.com/JdEveI
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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