Re: get_progname() should not be const char *?

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Tue, Feb 5, 2013 at 12:18 AM, Phil Sorber <phil(at)omniti(dot)com> wrote:
>> On Mon, Feb 4, 2013 at 10:52 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> I don't believe that callers should be trying to free() the result.
>>> Whether it's been strdup'd or not is not any of their business.

>> Is that just because of the nature of this specific function?

> I can't presume to speak for Tom, but I think so. Sometimes the API
> of a function includes the notion that the caller should pfree the
> result. Sometimes it doesn't. The advantage of NOT including that in
> the API contract is that you can sometimes do optimizations that would
> be impossible otherwise - e.g. you can return the same palloc'd string
> on successive calls to the function; or you can sometimes return a
> statically allocated string.

Yeah. In this particular case, it seems rather obvious that the
function should be returning the same string each time --- if it's
actually doing a fresh malloc, that sounds like a bug.

But in any case, adding or removing a const qualifier from a function's
result typically goes along with an API-contract change as to whether
the caller is supposed to free the result or not. My objection here
was specifically that I don't believe the contract for get_progname
includes caller-free now, and I don't want it to start being that.

regards, tom lane