Re: [libvirt] [PATCH] uml_conf.c: don't return an uninitialized pointer

Daniel Veillard wrote: Then perhaps I didn't explain well. Here's a small example: int foo (void) { int ret = 0; switch (f()) { case 0: do_something (); ret = -1; break; case 1: do_something_else (); ret = -1; break; default: ret = -2; break; } return ret; } In that function, the initialization of "ret" is officially unnecessary. Or, make it more like the code in question, initializing to the value used in the "default" case: int foo (void) { int ret = -2; switch (f()) { case 0: do_something (); ret = -1; break; case 1: do_something_else (); ret = -1; break; default: break; } return ret; } However, Dan argued that he wants to be sure "ret" is defined, in case someone else (one of the case stmts) forgets. However, that's precisely the case in which you do *not* want there to be an overarching definition, because with that "extra", initial assignment, the compiler cannot warn you if you add a case like this: case 2: // ...do things, but forget to set "ret" break; However, if you merely declare "ret", with no initial value, adding that erroneous "case 2" would provoke a warning about "ret" being used (via the return) undefined. I prefer to use the compiler as a safety net, whenever possible. I.e., imho, it is clear that this toy function should be written like this, with no initial assignment to "ret": int foo (void) { int ret; switch (f()) { case 0: do_something (); ret = -1; break; case 1: do_something_else (); ret = -1; break; default: ret = -2; break; } return ret; }