multiprocessrollingtest in macOS: fix compilation and the test itself

[RK-BFX]

Fixes #501:

1. Add necessary #includes to get the per-platform calls in GetExecutableFileName() to compile.
2. Fix buffer size passed to _NSGetExecutablePath() in macOS.

Plus:
A. Add more diagnostics for test failures like this.
B. Add useful TODO comments.

Also fix some linter warnings:
a. 3 signed-unsigned comparison mismatches;
b. 1 possibly unused variable.

[swebb2066]

Thanks for the fix.

To prevent future regressions, it may be advisable to include the multiprocessrollingtest in a CI task by adding to a MacOs task:

diff --git a/.github/workflows/log4cxx-macos.yml b/.github/workflows/log4cxx-macos.yml
index 21186763..55b56d23 100644
--- a/.github/workflows/log4cxx-macos.yml
+++ b/.github/workflows/log4cxx-macos.yml
@@ -31,16 +31,19 @@ jobs:
             cxx: clang++
             odbc: OFF
             qt: ON
+            multiprocess: OFF
           - name: osx-14
             os: macos-14
             cxx: clang++
             odbc: ON
             qt: OFF
+            multiprocess: ON
           - name: osx-g++
             os: macos-latest
             cxx: g++-14
             odbc: OFF
             qt: OFF
+            multiprocess: OFF

     steps:
     - uses: actions/checkout@v4
@@ -59,7 +62,13 @@ jobs:
         cd main
         mkdir build
         cd build
-        cmake -DCMAKE_CXX_COMPILER=${{ matrix.cxx }} -DLOG4CXX_ENABLE_ODBC=${{ matrix.odbc }} -DLOG4CXX_CFSTRING=ON -DCMAKE_BUILD_TYPE=Debug ..
+        cmake \
+          -DCMAKE_CXX_COMPILER=${{ matrix.cxx }} \
+          -DLOG4CXX_ENABLE_ODBC=${{ matrix.odbc }} \
+          -DLOG4CXX_MULTIPROCESS_ROLLING_FILE_APPENDER=${{ matrix.multiprocess }} \
+          -DLOG4CXX_CFSTRING=ON \
+          -DCMAKE_BUILD_TYPE=Debug \
+          ..
         cmake --build .

     - name: run unit tests

[RK-BFX]

it may be advisable to include the multiprocessrollingtest in a CI task by adding to a MacOs task

Am I supposed to include these changes to my PR? I don't have experience with GitHub CI and don't know how to test this.
If you're a maintainer, are you able to amend the PR accordingly?

[swebb2066]

Am I supposed to include these changes to my PR?

Yes, it helps the commit history to keep related changes together.

I don't have experience with GitHub CI and don't know how to test this.

Just apply that change an push the commit to the same branch. The GitHub actions will run when we (the maintainers) approve the change. The build logs from the Github action are available in a drop down list when you click the check-mark that getss added beside the commit hash.

[RK-BFX]

Wouldn't it make sense to add at least one Release build in the similar manner? E.g. a new one with all of multiprocess, odbc, and qt set to ON?

[swebb2066]

Leave the issue of what to test in CI for another day. Just apply the change to log4cxx-macos.yml so we can verify this change works.