Why do try..catch blocks require braces?

Question

While in other statements like if ... else you can avoid braces if there is only one instruction in a block, you cannot do that with try ... catch blocks: the compiler doesn't buy it. For instance:

try     do_something_risky(); catch (...)     std::cerr << "Blast!" << std::endl; 

With the code above, g++ simply says it expects a '{' before do_something_risky(). Why this difference of behavior between try ... catch and, say, if ... else ?

Thanks!

Answer 1

Straight from the C++ spec:

try-block:     try compound-statement handler-seq 

As you can see, all try-blocks expect a compound-statement. By definition a compound statement is multiple statements wrapped in braces.

Have everything in a compound-statement ensures that a new scope is generated for the try-block. It also makes everything slightly easier to read in my opinion.

You can check it yourself on page 359 of the C++ Language Specification

Answer 2

Not sure why, but one benefit is that there is no dangling-catch issue. See dangling-else for an ambiguity that can arise when braces are optional.