It’s a gcc-specific extension, a unary && operator that can be applied to a label name, yielding its address as a void* value. As part of the extension, goto *ptr; is allowed where ptr is an expression of type void*. It’s documented here in the gcc manual. You can get the address of a label … Read more
The C++ Standard says: On exit from a scope (however accomplished), destructors (12.4) are called for all constructed objects with automatic storage duration (3.7.2) (named objects or temporaries) that are declared in that scope, in the reverse order of their declaration. So the answer is “yes”.
Forgive me – I couldn’t resist 😉 def goto(linenum): global line line = linenum line = 1 while True: if line == 1: response = raw_input(“yes or no? “) if response == “yes”: goto(2) elif response == “no”: goto(3) else: goto(100) elif line == 2: print “Thank you for the yes!” goto(20) elif line == … Read more
Historical context: We should remember that Dijkstra wrote Goto Considered Harmful in 1968, when a lot of programmers used goto as a replacement for structured programming (if, while, for, etc.). It’s 44 years later, and it’s rare to find this use of goto in the wild. Structured programming has already won, long ago. Case analysis: … Read more
The size of the method code can be as large as 64K. The branch offset of the short goto is a signed 16-bit integer: from -32768 to 32767. So, the short offset is not enough to make a jump from the beginning of 65K method to the end. Even javac sometimes emits goto_w. Here is … Read more
This construct is illegal in C#: switch (variable) { case 2: Console.WriteLine(“variable is >= 2”); case 1: Console.WriteLine(“variable is >= 1”); } In C++, it would run both lines if variable = 2. It may be intentional but it’s too easy to forget break; at the end of the first case label. For this reason, … Read more
How many bugs have been introduced because of incorrectly written GOTOs? How much money did they cost the company? Turn the issue into something concrete, rather than “this feels bad”. Once you can get it recognized as a problem by the people in charge, turn it into a policy like, “no new GOTOs for anything … Read more
EDIT: How bad is the goto statement really, and why? It depends on the exact situation. I can’t remember any time where I found it made the code more readable than refactoring. It also depends on your personal view of readability – some people dislike it more than others, as is clear from the other … Read more
I am not sure what do you mean by clean up code but in C++ there is a concept called “resource acquisition is initialization” and it should be the responsibility of your destructors to clean up stuff. (Note that in C# and Java, this is usually solved by try/finally) For more info check out this … Read more
The C and C++ standards do not support this feature. However, the GNU Compiler Collection (GCC) includes a non-standard extension for doing this, as described in the Labels as Values section of the Using the GNU Compiler Collection manual. Essentially, they have added a special unary operator && that reports the address of the label … Read more