Re: Is RPG 'DEAD"

Jerry Adams wrote:

It was been > 20 years since I did any C or Assembler, and never C# or Java so maybe someone could explain to me why things like "memory leaks" and "buffer overflows" seem to be more topical in those languages and Wintel platforms than here?

Memory leaks are more common in other languages because manually allocated memory is not commonly used in RPG. If it were used more frequently, I suspect that RPG would be just as prone to memory leakage as C.

Java is less prone to memory leaks because the garbage collector takes care of deallocating memory when it is no longer referenced. It is still quite possible to accidentally keep a reference to memory that should be deallocated, and I would consider this to be memory leak as well. See http://www.ibm.com/developerworks/java/library/j-leaks/.

Buffer overflow is really a very general term for a program overwriting memory that it is not supposed to overwrite. A couple of RPG examples would be the much cited parameter mismatch and passing the wrong "bytes provided" length to an API that returns a variable length structure. If you search "parameter mismatch" in the archives you'll see that buffer overflows are not unheard of in the RPG world.

The reason you hear more about buffer overflows on other platforms is that they can cause security problems. IBM i makes a distinction between pointers to data and pointer to executable code which other popular platforms do not. Simplistically, if an attacker can arrange to have the overflowing program write a jump instruction to memory, they can cause the system to execute arbitrary code of their choosing, with all of the permissions of the program that was running.