Exception in C++ 学习笔记
前几天，在项目测试中又遇到了程序coredump，日志如下。
可以明显看到，程序APP（隐去真名）收到signal 6 （SIG_ABRT）然后coredump。
一般来说，应用程序收到SIGABRT是因为调用abort（）函数造成的。而abort()的调用，大部分是因为错误的
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+++ HPC7000BJ08 2014-02-28 22:20:40 MAINT #044467 0-1-13 >
** REPT INIT - CORE FILE /sn/core/APP/core DETECTED
END OF REPORT #044467++-
^A
+++ HPC7000BJ08 2014-02-28 22:20:40 MAINT #044468 0-1-13 >
*C REPT INIT DETECTED APP DIED
END OF REPORT #044468++-
^A
+++ HPC7000BJ08 2014-02-28 22:20:40 MAINT #044469 0-1-13 >
REPT INIT APP RECEIVED SIGNAL 6
END OF REPORT #044469++-
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
C++ Exceptions:
| Exception | Description |
|---|---|
| std::exception | An exception and parent class of all the standard C++ exceptions. |
| std::bad_alloc | This can be thrown by new. |
| std::bad_cast | This can be thrown by dynamic_cast. |
| std::bad_exception | This is useful device to handle unexpected exceptions in a C++ program |
| std::bad_typeid | This can be thrown by typeid. |
| std::logic_error | An exception that theoretically can be detected by reading the code. |
| std::domain_error | This is an exception thrown when a mathematically invalid domain is used |
| std::invalid_argument | This is thrown due to invalid arguments. |
| std::length_error | This is thrown when a too big std::string is created |
| std::out_of_range | This can be thrown by the at method from for example a std::vector and std::bitset<>::operator[](). |
| std::runtime_error | An exception that theoretically can not be detected by reading the code. |
| std::overflow_error | This is thrown if a mathematical overflow occurs. |
| std::range_error | This is occured when you try to store a value which is out of range. |
| std::underflow_error | This is thrown if a mathematical underflow occurs. |
值得注意的是一些我们经常能碰到的异常（红色）:
std::bad_alloc： thrown by the standard definitions of operator new and operator new[] when they fail to allocate the requested storage space.
默认的new 是要抛出异常的，如果想不抛异常而是置指针为NULL，需要使用new(std::nothrow)。
std::bad_cast： When dynamic_cast cannot cast a pointer because it is not a complete object of the required class -as in the second conversion in the previous example- it returns a null pointer to indicate the failure.
If dynamic_cast is used to convert to a reference type and the conversion is not possible, an exception of type bad_cast is thrown instead.
未捕获的异常处理方式如下：
If no handler at any level catches the exception, the special library function terminate( ) (declared in the <exception> header) is automatically called. By default, terminate( ) calls the Standard C library function abort( ) , which abruptly exits the program. On Unix systems, abort( ) also causes a core dump. When abort( ) is called, no calls to normal program termination functions occur, which means that destructors for global and static objects do not execute. The terminate( ) function also executes if a destructor for a local object throws an exception while the stack is unwinding (interrupting the exception that was in progress) or if a global or static object s constructor or destructor throws an exception. (In general, do not allow a destructor to throw an exception.)
Stack Unwinding
Constructors and Destructors
C++ exception specification有很多坑：
1. 函数原型里带throw的，如果使用typedef，会出现语法错误：
typedef void (*PF)() throw(A,B); // syntax error
2. 带来类型弱化：
void f() throw(A,B);
void (*pf)() throw(A,B,C); // ok
pf = f; // ok, less restrictive
总之，少用为宜。
