error: use of undeclared identifier 'MAP_ANONYMOUS'

[ryandesign]

s2 fails to build on OS X 10.10 and earlier:

https://trac.macports.org/ticket/67784

absl/debugging/internal/examine_stack.cc:58:34: error: use of undeclared identifier 'MAP_ANONYMOUS'
                   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
                                 ^
1 error generated.

MAP_ANONYMOUS is equivalent to MAP_ANON which is available on older systems.

There are several places where you already have code to address this:

s2/src/absl/base/internal/low_level_alloc.cc

Lines 56 to 63 in 4fe0c97

	// MAP_ANONYMOUS
	#if defined(__APPLE__)
	// For mmap, Linux defines both MAP_ANONYMOUS and MAP_ANON and says MAP_ANON is
	// deprecated. In Darwin, MAP_ANON is all there is.
	#if !defined MAP_ANONYMOUS
	#define MAP_ANONYMOUS MAP_ANON
	#endif // !MAP_ANONYMOUS
	#endif // __APPLE__

s2/src/absl/debugging/failure_signal_handler.cc

Lines 154 to 156 in 4fe0c97

	#if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)
	#define MAP_ANONYMOUS MAP_ANON
	#endif

s2/src/s2/base/port.h

Lines 574 to 581 in 4fe0c97

	// MAP_ANONYMOUS
	#if defined(__APPLE__)
	// For mmap, Linux defines both MAP_ANONYMOUS and MAP_ANON and says MAP_ANON is
	// deprecated. In Darwin, MAP_ANON is all there is.
	#if !defined MAP_ANONYMOUS
	#define MAP_ANONYMOUS MAP_ANON
	#endif // !MAP_ANONYMOUS
	#endif // __APPLE__

Note that the comment is outdated: MAP_ANONYMOUS does exist on Darwin in OS X 10.11 (released 2015) and later.

There are two places where similar code needs to be added, or it needs to be moved into a more central include file:

s2/src/absl/debugging/internal/examine_stack.cc

Lines 57 to 58 in 4fe0c97

	void* p = ::mmap(nullptr, num_bytes, PROT_READ | PROT_WRITE,
	MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);

s2/src/absl/debugging/internal/stack_consumption.cc

Lines 113 to 114 in 4fe0c97

	void* altstack = mmap(nullptr, kAlternateStackSize, PROT_READ | PROT_WRITE,
	MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);

I see no reason to limit the fix to systems where __APPLE__ is defined.

[ryandesign]

There are two places where similar code needs to be added

For example like this:

https://github.com/macports/macports-ports/blob/6102b5d9c70d7c21c9d20f79ce9ff65fc2b77772/R/R-s2/files/MAP_ANON.patch

[paleolimbot]

Thank you for reporting! We are about to update abseil and S2 to newer versions. Do you know if abseil-cpp and the latest version of google/s2geometry are able to compile on macports?

[ryandesign]

I did not see this fix in the upstream abseil repository.

In MacPorts, the abseil port works around the problem by using a compatibility library developed by MacPorts which includes, among other things, the missing MAP_ANONYMOUS definition. It would be better to report the problem to the developers of abseil however so they can fix it.

[ryandesign]

Build status information for abseil and s2geometry in MacPorts are here:

https://ports.macports.org/port/abseil/details/

https://ports.macports.org/port/s2geometry/details/

[ryandesign]

It would be better to report the problem to the developers of abseil however so they can fix it.

abseil/abseil-cpp#1500

[ryandesign]

But abseil also now uses clock_gettime which is only available in macOS 10.12 and later. I reported this to them and they will not fix it; they state abseil requires macOS 10.13 or later. For MacPorts, we have a clock_gettime implementation in our compatibility library.