On 03/08/2013 11:26 AM, Rob T wrote:
On Friday, 8 March 2013 at 17:40:38 UTC, Ali Çehreli wrote:
On 03/08/2013 12:39 AM, Rob T wrote:
> In C++ you can do this
>
> std::exception Trace()
> {
> try
> {
> // key item missing from D
> throw; // <= rethrow last exception
This idiom is know as a Lippincott Function.
Ali
I'm having trouble finding references on Lippincott Function, so if you
have any more information, please let me know. Thanks.
--rt
I heard about this idiom for the first time in Jon Kalb's talk. The name
appears in his slides:
http://exceptionsafecode.com/
Very smart way of writing a single function that catches many different
types of exceptions; does special things about them, like producing
special error codes, and then returns those codes to the C world.
I am familiar with your use case: When a C layer calls C++, the
exceptions must be caught and converted to error codes. This is how we
do it:
#define BEGIN_C_INTERFACE try {
#define END_C_INTERFACE \
} catch (const SomeType & e) { \
// ... special code for SomeType \
} catch (const SomeOtherType & e) { \
// ... special code for SomeOtherType \
\
// ... etc. \
\
} catch( ... ) { \
log("Unhandled exception"); \
return some_generic_error_code; \
}
Then our C++ functions that are called from C are like this:
extern "C"
int my_api_func()
{
BEGIN_C_INTERFACE
// ... the actual body of the function
END_C_INTERFACE
}
Lippincott functions avoid macros and make it more explicit that the
entire body is inside a try block.
Ali
