fork download 
  1. #include <exception>
  2. #include <iostream>
  3. #include <ostream>
  4. #include <string>
  5.  
  6. using namespace std;
  7.  
  8. // ________________ uncaught_exception_count implementation ________________
  9. extern "C" char * _getptd();
  10. int uncaught_exception_count()
  11. {
  12. 	// MSVC specific. Tested on MSVC2010SP1 x32 and x64.
  13. 	return *(static_cast<int*>(static_cast<void*>( _getptd() + (sizeof(void*)==8 ? 0x100 : 0x90) ))); // x32 offset - 0x90 , x64 - 0x100
  14. }
  15.  
  16. // ________________ uncaught_exception_count test __________________________
  17. struct T800
  18. {
  19. 	~T800()
  20. 	{
  21. 		cout << "uncaught_exception_count=" << uncaught_exception_count() << endl;
  22. 	}
  23. };
  24.  
  25. struct ThrowableDestructor
  26. {
  27. 	~ThrowableDestructor()
  28. 	{
  29. 		throw 0;
  30. 	}
  31. };
  32.  
  33. template<typename FirstScoped, typename SecondScoped=ThrowableDestructor>
  34. struct ExptSwallower
  35. {
  36. 	~ExptSwallower()
  37. 	{
  38. 		try
  39. 		{
  40. 			FirstScoped a;
  41. 			SecondScoped b;
  42. 		}catch(...){}
  43. 	}
  44. };
  45.  
  46. void uncaught_exception_count_demo()
  47. {
  48. 	T800 a;
  49. 	ExptSwallower<T800> b;
  50. 	ExptSwallower<ExptSwallower<T800> > c;
  51. 	ExptSwallower<ExptSwallower<ExptSwallower<T800> > > d;
  52. 	ExptSwallower<ExptSwallower<ExptSwallower<ExptSwallower<T800> > > > e;
  53. }
  54.  
  55. // ________________ Advanced Scope Guard ___________________________________
  56.  
  57. // Refer Andrei Alexandrescu talk at:
  58. // http://c...content-available-to-author-only...n.com/Events/Lang-NEXT/Lang-NEXT-2012/Three-Unlikely-Successful-Features-of-D
  59. class DLikeScopeGuard
  60. {
  61. 	int exception_enter_state;
  62. public:
  63. 	DLikeScopeGuard()
  64. 	{
  65. 		exception_enter_state=uncaught_exception_count();
  66. 	}
  67. 	void scope_success()
  68. 	{
  69. 		cout << "scope_success" << endl;
  70. 	}
  71. 	void scope_failure()
  72. 	{
  73. 		cout << "scope_failure" << endl;
  74. 	}
  75. 	void scope_exit()
  76. 	{
  77. 		cout << "scope_exit" << endl;
  78. 	}
  79. 	~DLikeScopeGuard()
  80. 	{
  81. 		if(exception_enter_state==uncaught_exception_count())
  82. 			scope_success();
  83. 		else
  84. 			scope_failure();
  85. 		scope_exit();
  86. 	}
  87. };
  88.  
  89. void scope_guard_demo()
  90. {
  91. 	{
  92. 		cout << endl << "no exception:" << endl;
  93. 		DLikeScopeGuard success;
  94. 	}
  95. 	try
  96. 	{
  97. 		cout << endl << "basic throw:" << endl;
  98. 		DLikeScopeGuard fail;
  99. 		throw 0;
  100. 	}catch(...){}
  101. 	try
  102. 	{
  103. 		cout << endl << "fail in previous destructor:" << endl;
  104. 		DLikeScopeGuard fail;
  105. 		ThrowableDestructor d;
  106. 	}catch(...){}
  107. 	try
  108. 	{
  109. 		cout << endl << "fail in next destructor:" << endl;
  110. 		ThrowableDestructor d;
  111. 		DLikeScopeGuard success;
  112. 	}catch(...){}
  113. 	try
  114. 	{
  115. 		cout << endl << "ExptSwallower<DLikeScopeGuard,ThrowableDestructor> during throw:" << endl;
  116. 		ExptSwallower<DLikeScopeGuard,ThrowableDestructor> fail;
  117. 		throw 0;
  118. 	}catch(...){}
  119. 	try
  120. 	{
  121. 		cout << endl << "ExptSwallower<ThrowableDestructor,DLikeScopeGuard> during throw:" << endl;
  122. 		ExptSwallower<ThrowableDestructor,DLikeScopeGuard> fail;
  123. 		throw 0;
  124. 	}catch(...){}
  125. 	try
  126. 	{
  127. 		cout << endl << "ExptSwallower<DLikeScopeGuard,int> during throw:" << endl;
  128. 		ExptSwallower<DLikeScopeGuard,int> success;
  129. 		throw 0;
  130. 	}catch(...){}
  131. }
  132.  
  133. int main(int argc,char *argv[])
  134. {
  135. 	cout << "uncaught_exception_count demo:" << endl << endl;
  136. 	uncaught_exception_count_demo();
  137. 	cout << std::string(25,'_') << endl;
  138. 	cout << "scope_guard demo:" << endl;
  139. 	scope_guard_demo();
  140. 	return 0;
  141. }
  142.  
  143.  
Not running #stdin #stdout 0s 0KB
comments (?)
stdin 
Standard input is empty
stdout 
Standard output is empty
https://ideone.com/IWiJu
language:
C++ (gcc 8.3)
created:
13 years ago
visibility:
secret

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!