Re: [MacPorts] #58645: physfs @3.0.1: error: ‘autoreleasepool’ undeclared (was: Physfs fails to build Mac OSX 10.5 Leopard)

[MacPorts]

#58645: physfs @3.0.1: error: ‘autoreleasepool’ undeclared
-----------------------------+---------------------------
  Reporter:  linuxjunkie999  |      Owner:  (none)
      Type:  defect          |     Status:  new
  Priority:  Normal          |  Milestone:
 Component:  ports           |    Version:  2.5.4
Resolution:                  |   Keywords:  tiger leopard
      Port:  physfs          |
-----------------------------+---------------------------
Changes (by ryandesign):

 * keywords:  leopard => tiger leopard


Comment:

 > `@autoreleasepool` change to `NSAutoreleasePool;`

 That's definitely not the correct fix.

 `@autoreleasepool` automatically creates an `NSAutoreleasePool` for the
 duration of the block. This notation is required when using Automatic
 Reference Counting, and modern macOS requires ARC. This notation also
 works correctly on pre-ARC systems, but only if you're using clang from
 Xcode 4.2 or later, and your log shows you're not using clang but rather
 gcc-4.2. It also shows you're on PowerPC, and we haven't gotten clang to
 work on PowerPC yet.

 Lacking the ability to use `@autoreleasepool`, the way to get this code to
 work on older systems would be to create and destroy the
 `NSAutoreleasePool` manually. That is, instead of:

 {{{
 @autoreleasepool {
     ...
 }
 }}}

 it would need to be:

 {{{
 NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
 ...
 [pool release];
 }}}

 And since that older style is not compatible with ARC, we would need to
 determine at compile time whether `@autoreleasepool` is available and use
 the right code for each case.

 Your suggested statement `NSAutoreleasePool;` is a no-op: it does nothing.
 (`NSAutoreleasePool` is a type; you've just mentioned a type on a line by
 itself, without doing anything with that type such as declaring a variable
 of that type and assigning something to it.) Your suggestion does not set
 up an autorelease pool, so it just results in leaking all the memory that
 the autorelease pool should have been releasing.

 In any case, we are not the developers of physfs. This is really an issue
 that should be reported to the developers of physfs so that they can fix
 it. I am not sure how much they care about older systems, but they did in
 the 3.0.2 release this year accept some patches from me and Ken to fix
 building on 10.7, so they may be interested, especially if the fix can be
 provided to them.

-- 
Ticket URL: <https://trac.macports.org/ticket/58645#comment:3>
MacPorts <https://www.macports.org/>
Ports system for macOS