error: use of undeclared identifier 'MAP_ANONYMOUS'

Open

#245 opened on Jul 29, 2023 6 comments 1 reaction 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty: 2/5
Estimated time: 1-3 hours
Newbie friendliness: 38/100

Issue type: Bug
Clarity: Clearly specified
Activity status: Stale
Tech stack: cpp, macos
Domain: build-system, operating-systems

Research direction

Start with absl/debugging/internal/examine_stack.cc and absl/debugging/internal/stack_consumption.cc, then compare the existing portability handling in low_level_alloc.cc, failure_signal_handler.cc, and s2/base/port.h. Confirm the compatibility change covers OS X 10.10 and earlier, while preserving behavior on newer Darwin systems, and verify that s2 builds successfully.

Written by the indexing model from the issue text.

Description

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:

https://github.com/r-spatial/s2/blob/4fe0c97df91c98a24f379bfc3d8d4544f4835117/src/absl/base/internal/low_level_alloc.cc#L56-L63

https://github.com/r-spatial/s2/blob/4fe0c97df91c98a24f379bfc3d8d4544f4835117/src/absl/debugging/failure_signal_handler.cc#L154-L156

https://github.com/r-spatial/s2/blob/4fe0c97df91c98a24f379bfc3d8d4544f4835117/src/s2/base/port.h#L574-L581

Note that the comment is outdated: MAP_ANONYMOUS does exist on Darwin in OS X 10.11 (released 2015) and later.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

https://github.com/r-spatial/s2/blob/4fe0c97df91c98a24f379bfc3d8d4544f4835117/src/absl/debugging/internal/examine_stack.cc#L57-L58

https://github.com/r-spatial/s2/blob/4fe0c97df91c98a24f379bfc3d8d4544f4835117/src/absl/debugging/internal/stack_consumption.cc#L113-L114

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

Dominant language: C++
Stars: 81
Forks: 19
Avg merge: 20h 25m
Merged PRs (30d): 3

Contributor guide

No contributing guide indexed for this repository

First steps

Read the whole issue, then the project's contributing guide.
Comment on the issue to say you are picking it up — it saves two people doing the same work.
Fork the repository and make your change on a branch.
Open a pull request that references the issue number.

Similar issues

Eval bug: SIGSEGV in token-counting routes when the request arrives while the server is sleeping (stale vocab/mctx captured before the wake barrier) Open

Difficulty 2/5 1-3 hours Newbie friendliness 86/100

ggml-org/llama.cpp#29188 · Opened Sep 20, 2026
Sensor initialization takes very long when `--initial-sim-time` is set to current UNIX timestamp Open

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

gazebosim/gz-sensors#662 · 1 comment · Opened Sep 20, 2026
Aligned columns on the serial monitor while keeping CSV on the SD card Open

enhancement

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

NorthernWidget/Margay_Library#31 · Opened Sep 20, 2026
v1 manifest list: existing_files_count is the table-wide total-data-files Open

comp-datalake

Difficulty 2/5 1-3 hours Newbie friendliness 88/100

ClickHouse/ClickHouse#121222 · Opened Sep 20, 2026
Case collision between `Canvas` and `canvas` test directories causes platform-dependent source hashes Open

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

LadybirdBrowser/ladybird#12123 · Opened Sep 20, 2026

More C++ issues