Re: Usage of throw
Olivier Delannoy wrote:
Hi all,
I am interesting in adding contextual information (such as file/line)
in debug mode and not in production mode. In order to do that I plan
on adding a macro of the form :
MY_THROW(exp) which is going to be translated into :
- in release mode: throw (exp)
- in debug mode: throw (exp).context(__FILE__, __LINE__)
In order to do that I need to make sure all my exception provide a
context method of the form :
class MyExp
{
...
public:
MyExp& context(char* file, int line) { ... ; return *this;}
};
Now in a test program I do:
void f()
{
MY_THROW(MyExp()); // In Debug mode: throw
(MyExp()).context(__FILE__, __LINE__);
}
int main()
{
try
{
f();
}
catch(MyExp& e)
{
// Do something with e
}
}
This program works nice but I don't feel confortable with this kind of
use of throw. Is it safe/portable accross compiler/ in respect of
standards to throw an exception as I do ?
Looks to be legal to me.
The one thing I'd do is have context take a const char* as the first
param instead of a char*.
Alternatively, have multiple constructors and instead of putting
MyExp() as the arg, try this:
class MyExp {
public:
MyExp() { /* ... */ }
MyExp(const char *file, const char *line) { /* ... */ }
// ...
};
#ifdef DEBUG
#define MY_THROW(type) throw(type(__FILE__,__LINE__))
#else
#define MY_THROW(type) throw(type())
#endif
int main()
{
try {
MY_THROW(MyExp);
}
catch (MyExp&)
{
]
}
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