# size_t vs "unsigned long" 8 messages from 2007-10-03 to 2007-10-05. Participants: Junio C Hamano, Pierre Habouzit, Jan Wielemaker, Florian Weimer, Kyle Moffett. Thread: https://gitlist.dev/t/10131 ## Junio C Hamano, 2007-10-03 20:30 Subject: size_t vs "unsigned long" Message-ID: <7vabr0djqr.fsf@gitster.siamese.dyndns.org> URL: https://gitlist.dev/e/7vabr0djqr.fsf%40gitster.siamese.dyndns.org ``` Traditionally, inside git, we have used the length of things with "unsigned long" for pretty much anything, except where we wanted the length exactly sized we used int32_t, uint64_t and friends. A few places pass pointer to unsigned long as the second parameter to strbuf_detach(), triggering type mismatch warnings. An easy way out is to change strbuf_detach() to take a pointer to ulong but I think it is going backwards. Most places that use "unsigned long" can safely be converted (and made more correct) to use size_t. Any opinions? ``` ## Pierre Habouzit, 2007-10-03 20:48 Subject: Re: size_t vs "unsigned long" Message-ID: <20071003204801.GC28188@artemis.corp> URL: https://gitlist.dev/e/20071003204801.GC28188%40artemis.corp In-Reply-To: <7vabr0djqr.fsf@gitster.siamese.dyndns.org> ``` On Wed, Oct 03, 2007 at 08:30:04PM +0000, Junio C Hamano wrote: > Traditionally, inside git, we have used the length of things > with "unsigned long" for pretty much anything, except where we > wanted the length exactly sized we used int32_t, uint64_t and > friends. > > A few places pass pointer to unsigned long as the second > parameter to strbuf_detach(), triggering type mismatch warnings. > An easy way out is to change strbuf_detach() to take a pointer > to ulong but I think it is going backwards. Most places that > use "unsigned long" can safely be converted (and made more > correct) to use size_t. Well, afaict, on every linux archs I know of, unsigned longs and size_t are the same. Though, I don't know if that holds for the msys port, and if that does not holds, then a s/unsigned long/size_t/ would help them. Else, for consistency sake, I believe the change is a good one. -- ·O· Pierre Habouzit ··O madcoder@debian.org OOO http://www.madism.org ``` ## Junio C Hamano, 2007-10-03 21:05 Subject: Re: size_t vs "unsigned long" Message-ID: <7v641newom.fsf@gitster.siamese.dyndns.org> URL: https://gitlist.dev/e/7v641newom.fsf%40gitster.siamese.dyndns.org In-Reply-To: <20071003204801.GC28188@artemis.corp> ``` Pierre Habouzit writes: > Well, afaict, on every linux archs I know of, unsigned longs and > size_t are the same. Though, I don't know if that holds for the msys > port, and if that does not holds, then a s/unsigned long/size_t/ would > help them. Else, for consistency sake, I believe the change is a good > one. FWIW, I am already getting bitten on a FC box with gcc 4.1.1 20060525 that warns about the wrong type being passed, as I usually build things with -Werror; the issue is not just "they are of the same underlying type". ``` ## Jan Wielemaker, 2007-10-03 21:19 Subject: Re: size_t vs "unsigned long" Message-ID: <200710032320.00263.wielemak@science.uva.nl> URL: https://gitlist.dev/e/200710032320.00263.wielemak%40science.uva.nl In-Reply-To: <20071003204801.GC28188@artemis.corp> ``` On Wednesday 03 October 2007 22:48, Pierre Habouzit wrote: > On Wed, Oct 03, 2007 at 08:30:04PM +0000, Junio C Hamano wrote: > > Traditionally, inside git, we have used the length of things > > with "unsigned long" for pretty much anything, except where we > > wanted the length exactly sized we used int32_t, uint64_t and > > friends. > > > > A few places pass pointer to unsigned long as the second > > parameter to strbuf_detach(), triggering type mismatch warnings. > > An easy way out is to change strbuf_detach() to take a pointer > > to ulong but I think it is going backwards. Most places that > > use "unsigned long" can safely be converted (and made more > > correct) to use size_t. > > Well, afaict, on every linux archs I know of, unsigned longs and > size_t are the same. Though, I don't know if that holds for the msys > port, and if that does not holds, then a s/unsigned long/size_t/ would > help them. Else, for consistency sake, I believe the change is a good > one. Surely on the Microsoft 64-bit compilers size_t is 64-bits and long is 32-bits. Don't blame me, I'm just the messenger that learned the hard way ... --- Jan ``` ## Pierre Habouzit, 2007-10-03 21:36 Subject: Re: size_t vs "unsigned long" Message-ID: <20071003213601.GD28188@artemis.corp> URL: https://gitlist.dev/e/20071003213601.GD28188%40artemis.corp In-Reply-To: <200710032320.00263.wielemak@science.uva.nl> ``` On Wed, Oct 03, 2007 at 09:19:59PM +0000, Jan Wielemaker wrote: > On Wednesday 03 October 2007 22:48, Pierre Habouzit wrote: > > On Wed, Oct 03, 2007 at 08:30:04PM +0000, Junio C Hamano wrote: > > > Traditionally, inside git, we have used the length of things > > > with "unsigned long" for pretty much anything, except where we > > > wanted the length exactly sized we used int32_t, uint64_t and > > > friends. > > > > > > A few places pass pointer to unsigned long as the second > > > parameter to strbuf_detach(), triggering type mismatch warnings. > > > An easy way out is to change strbuf_detach() to take a pointer > > > to ulong but I think it is going backwards. Most places that > > > use "unsigned long" can safely be converted (and made more > > > correct) to use size_t. > > > > Well, afaict, on every linux archs I know of, unsigned longs and > > size_t are the same. Though, I don't know if that holds for the msys > > port, and if that does not holds, then a s/unsigned long/size_t/ would > > help them. Else, for consistency sake, I believe the change is a good > > one. > > Surely on the Microsoft 64-bit compilers size_t is 64-bits and long is > 32-bits. Don't blame me, I'm just the messenger that learned the hard > way ... Yeah, I've been wondering, and it's the information I had. well, the information I had is that sizeof(size_t) is 4 on win32, and 8 on win64, OTOH (and this one I'm sure), on windows, longs are 32bits on both (32 and 64 bits ABIs). So replacing unsigned long with size_t's will help the msys port, hence I had some insight that this could prove useful, now I'm sure :) -- ·O· Pierre Habouzit ··O madcoder@debian.org OOO http://www.madism.org ``` ## Florian Weimer, 2007-10-03 21:36 Subject: Re: size_t vs "unsigned long" Message-ID: <877im3khj0.fsf@mid.deneb.enyo.de> URL: https://gitlist.dev/e/877im3khj0.fsf%40mid.deneb.enyo.de In-Reply-To: <20071003204801.GC28188@artemis.corp> ``` * Pierre Habouzit: > Well, afaict, on every linux archs I know of, unsigned longs and > size_t are the same. IIRC, 64-bit Windows uses 64-bit points (duh) and hence a 64-bit size_t, but still has got 32-bit longs. Documentation is a bit sparse on this matter (because you are supposed to use LONG, DWORD and friends anyway). ``` ## Jan Wielemaker, 2007-10-04 07:16 Subject: Re: size_t vs "unsigned long" Message-ID: <200710040916.55998.wielemak@science.uva.nl> URL: https://gitlist.dev/e/200710040916.55998.wielemak%40science.uva.nl In-Reply-To: <20071003213601.GD28188@artemis.corp> ``` On Wednesday 03 October 2007 23:36, Pierre Habouzit wrote: > On Wed, Oct 03, 2007 at 09:19:59PM +0000, Jan Wielemaker wrote: > > On Wednesday 03 October 2007 22:48, Pierre Habouzit wrote: > > > On Wed, Oct 03, 2007 at 08:30:04PM +0000, Junio C Hamano wrote: > > > > Traditionally, inside git, we have used the length of things > > > > with "unsigned long" for pretty much anything, except where we > > > > wanted the length exactly sized we used int32_t, uint64_t and > > > > friends. > > > > > > > > A few places pass pointer to unsigned long as the second > > > > parameter to strbuf_detach(), triggering type mismatch warnings. > > > > An easy way out is to change strbuf_detach() to take a pointer > > > > to ulong but I think it is going backwards. Most places that > > > > use "unsigned long" can safely be converted (and made more > > > > correct) to use size_t. > > > > > > Well, afaict, on every linux archs I know of, unsigned longs and > > > size_t are the same. Though, I don't know if that holds for the msys > > > port, and if that does not holds, then a s/unsigned long/size_t/ would > > > help them. Else, for consistency sake, I believe the change is a good > > > one. > > > > Surely on the Microsoft 64-bit compilers size_t is 64-bits and long is > > 32-bits. Don't blame me, I'm just the messenger that learned the hard > > way ... > > Yeah, I've been wondering, and it's the information I had. well, the > information I had is that sizeof(size_t) is 4 on win32, and 8 on win64, > OTOH (and this one I'm sure), on windows, longs are 32bits on both (32 > and 64 bits ABIs). > > So replacing unsigned long with size_t's will help the msys port, > hence I had some insight that this could prove useful, now I'm sure :) The other types that are useful are intptr_t and uintptr_t, integers that are guaranteed to be able to hold a pointer. They are defined by recent versions of the Microsoft compilers and are in in most POSIX systems (at least I didn't have complaints since I started using them). I use them for integers holding mangled pointers. Of course most clean C programs should not need that. --- Jan ``` ## Kyle Moffett, 2007-10-05 06:27 Subject: Re: size_t vs "unsigned long" Message-ID: <620B5C1C-CFE8-401B-8BC7-D89C8740D63B@mac.com> URL: https://gitlist.dev/e/620B5C1C-CFE8-401B-8BC7-D89C8740D63B%40mac.com In-Reply-To: <877im3khj0.fsf@mid.deneb.enyo.de> ``` On Oct 03, 2007, at 17:36:03, Florian Weimer wrote: > * Pierre Habouzit: >> Well, afaict, on every linux archs I know of, unsigned longs and >> size_t are the same. > > IIRC, 64-bit Windows uses 64-bit points (duh) and hence a 64-bit > size_t, but still has got 32-bit longs. Documentation is a bit > sparse on this matter (because you are supposed to use LONG, DWORD > and friends anyway). For reference, Linux is always an LP32 (long-and-pointer-are-32-bit) or LP64 (long-and-pointer-are-64-bit) platform. On the other hand, for crappy backwards-compat reasons, Windows is either LP32 or LLP64 (long-long-and-pointer-are-64-bit). I think most of the remaining UNIXes fall into the LP32/LP64 category, the LLP64 platforms are fairly rare (thankfully). Cheers, Kyle Moffett ```