System and device programming-exception example
// exceptions_try_except_Statement.cpp
Syntax
__try
{
// guarded code
}
__except ( expression )
{
// exception handler code
}
https://msdn.microsoft.com/en-us/library/s58ftw19.aspx
// Example of try-except and try-finally statements
#include <stdio.h>
#include <windows.h> // for EXCEPTION_ACCESS_VIOLATION
#include <excpt.h>
int filter(unsigned int code, struct _EXCEPTION_POINTERS *ep) {
puts("in filter.");
if (code == EXCEPTION_ACCESS_VIOLATION) {
puts("caught AV as expected.");
return EXCEPTION_EXECUTE_HANDLER;
}
else {
puts("didn't catch AV, unexpected.");
return EXCEPTION_CONTINUE_SEARCH;
};
}
int main()
{
int* p = 0x00000000; // pointer to NULL
puts("hello");
__try{
puts("in try");
__try{
puts("in try");
*p = 13; // causes an access violation exception;
}__finally{
puts("in finally. termination: ");
puts(AbnormalTermination() ? "\tabnormal" : "\tnormal");
}
}__except(filter(GetExceptionCode(), GetExceptionInformation())){
puts("in except");
}
puts("world");
}
Output:
hello
in try
in try
in filter.
caught AV as expected.
in finally. termination:
abnormal
in except
world
when block *p=13,result is:
hello
in try1
in try2
in finally. termination:
normal
world
（to print 16进制 using %x）
when change the order:
int main()
{
int* p = 0x00000000; // pointer to NULL
puts("hello");
__try{
puts("in try1");
__try{
puts("in try2");
*p = 13; // causes an access violation exception;
}__except(filter(GetExceptionCode(), GetExceptionInformation())){
puts("in except");
}
}__finally{
puts("in finally. termination: ");
puts(AbnormalTermination() ? "\tabnormal" : "\tnormal");
}
puts("world");
Sleep(2000000);
}
result is:
hello
in try1
in try2
in filter.
exception code is c0000005
caught AV as expected.
in except
in finally. termination:
normal
world
now finally is corresponding to outer try,so of course,the outer try has no error,
the function AbnormalTermination() won't detect error
And through the code can find the exception is not user-generated(c not E),can use ReportException() to define user generated exception.