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.  
  10. #if defined(_MSC_VER)
  11. extern "C" char * _getptd();
  12. int uncaught_exception_count()
  13. {
  14. 	// MSVC specific. Tested on MSVC2010SP1 x32 and x64.
  15. 	return *(static_cast<int*>(static_cast<void*>( _getptd() + (sizeof(void*)==8 ? 0x100 : 0x90) ))); // x32 offset - 0x90 , x64 - 0x100
  16. }
  17. #elif defined(__GNUG__)
  18. extern "C" char * __cxa_get_globals();
  19. int uncaught_exception_count()
  20. {
  21. 	return *(static_cast<int*>(static_cast<void*>( __cxa_get_globals() + (sizeof(void*)==8 ? 0x8 : 0x4) ))); // x32 offset - 0x4 , x64 - 0x8
  22. }
  23. #endif
  24.  
  25. // ________________ uncaught_exception_count test __________________________
  26. struct T800
  27. {
  28. 	~T800()
  29. 	{
  30. 		cout << "uncaught_exception_count=" << uncaught_exception_count() << endl;
  31. 	}
  32. };
  33.  
  34. struct ThrowableDestructor
  35. {
  36. 	~ThrowableDestructor()
  37. 	{
  38. 		throw 0;
  39. 	}
  40. };
  41.  
  42. template<typename FirstScoped, typename SecondScoped=ThrowableDestructor>
  43. struct ExptSwallower
  44. {
  45. 	~ExptSwallower()
  46. 	{
  47. 		try
  48. 		{
  49. 			FirstScoped a;
  50. 			SecondScoped b;
  51. 		}catch(...){}
  52. 	}
  53. };
  54.  
  55. void uncaught_exception_count_demo()
  56. {
  57. 	T800 a;
  58. 	ExptSwallower<T800> b;
  59. 	ExptSwallower<ExptSwallower<T800> > c;
  60. 	ExptSwallower<ExptSwallower<ExptSwallower<T800> > > d;
  61. 	ExptSwallower<ExptSwallower<ExptSwallower<ExptSwallower<T800> > > > e;
  62. }
  63.  
  64. // ________________ Advanced Scope Guard ___________________________________
  65.  
  66. // Refer Andrei Alexandrescu talk at:
  67. // http://c...content-available-to-author-only...n.com/Events/Lang-NEXT/Lang-NEXT-2012/Three-Unlikely-Successful-Features-of-D
  68. class DLikeScopeGuard
  69. {
  70. 	int exception_enter_state;
  71. public:
  72. 	DLikeScopeGuard()
  73. 	{
  74. 		exception_enter_state=uncaught_exception_count();
  75. 	}
  76. 	void scope_success()
  77. 	{
  78. 		cout << "scope_success" << endl;
  79. 	}
  80. 	void scope_failure()
  81. 	{
  82. 		cout << "scope_failure" << endl;
  83. 	}
  84. 	void scope_exit()
  85. 	{
  86. 		cout << "scope_exit" << endl;
  87. 	}
  88. 	~DLikeScopeGuard()
  89. 	{
  90. 		if(exception_enter_state==uncaught_exception_count())
  91. 			scope_success();
  92. 		else
  93. 			scope_failure();
  94. 		scope_exit();
  95. 	}
  96. };
  97.  
  98. void scope_guard_demo()
  99. {
  100. 	{
  101. 		cout << endl << "no exception:" << endl;
  102. 		DLikeScopeGuard success;
  103. 	}
  104. 	try
  105. 	{
  106. 		cout << endl << "basic throw:" << endl;
  107. 		DLikeScopeGuard fail;
  108. 		throw 0;
  109. 	}catch(...){}
  110. 	try
  111. 	{
  112. 		cout << endl << "fail in previous destructor:" << endl;
  113. 		DLikeScopeGuard fail;
  114. 		ThrowableDestructor d;
  115. 	}catch(...){}
  116. 	try
  117. 	{
  118. 		cout << endl << "fail in next destructor:" << endl;
  119. 		ThrowableDestructor d;
  120. 		DLikeScopeGuard success;
  121. 	}catch(...){}
  122. 	try
  123. 	{
  124. 		cout << endl << "ExptSwallower<DLikeScopeGuard,ThrowableDestructor> during throw:" << endl;
  125. 		ExptSwallower<DLikeScopeGuard,ThrowableDestructor> fail;
  126. 		throw 0;
  127. 	}catch(...){}
  128. 	try
  129. 	{
  130. 		cout << endl << "ExptSwallower<ThrowableDestructor,DLikeScopeGuard> during throw:" << endl;
  131. 		ExptSwallower<ThrowableDestructor,DLikeScopeGuard> fail;
  132. 		throw 0;
  133. 	}catch(...){}
  134. 	try
  135. 	{
  136. 		cout << endl << "ExptSwallower<DLikeScopeGuard,int> during throw:" << endl;
  137. 		ExptSwallower<DLikeScopeGuard,int> success;
  138. 		throw 0;
  139. 	}catch(...){}
  140. }
  141.  
  142. int main(int argc,char *argv[])
  143. {
  144. 	cout << "uncaught_exception_count demo:" << endl << endl;
  145. 	uncaught_exception_count_demo();
  146. 	cout << std::string(25,'_') << endl;
  147. 	cout << "scope_guard demo:" << endl;
  148. 	scope_guard_demo();
  149. 	return 0;
  150. }
  151.  
  152.  
Success #stdin #stdout 0.01s 2860KB
comments (?)
stdin 
Standard input is empty
stdout 
uncaught_exception_count demo:

uncaught_exception_count=4
uncaught_exception_count=3
uncaught_exception_count=2
uncaught_exception_count=1
uncaught_exception_count=0
_________________________
scope_guard demo:

no exception:
scope_success
scope_exit

basic throw:
scope_failure
scope_exit

fail in previous destructor:
scope_failure
scope_exit

fail in next destructor:
scope_success
scope_exit

ExptSwallower<DLikeScopeGuard,ThrowableDestructor> during throw:
scope_failure
scope_exit

ExptSwallower<ThrowableDestructor,DLikeScopeGuard> during throw:
scope_success
scope_exit

ExptSwallower<DLikeScopeGuard,int> during throw:
scope_success
scope_exit
https://ideone.com/zA4Po
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!