Remove custom deduction guides for std::unique_ptr in C++17 mode.
Issue: FreeBSD GCC 13.3 correctly rejects adding deduction guides
to namespace std, which violates C++ standard [namespace.std]:
"The behavior of a C++ program is undefined if it adds declarations
or definitions to namespace std or to a namespace within namespace std."
Root cause: The code attempted to add custom deduction guides for
std::unique_ptr in namespace std when compiling in C++17 mode.
This is not allowed by the C++ standard.
Solution: Remove the custom deduction guides for C++17 and later,
as the C++17 standard library already provides deduction guides
for std::unique_ptr (added in C++17 via P0433R2).
The custom deduction guide wrappers in the else branch (for C++14
and earlier) are kept as they provide helper functions, not actual
deduction guides in namespace std.
Tested-on: FreeBSD 15 with GCC 13.3
Fixes: Compilation error 'deduction guide must be declared in the
same scope as template std::unique_ptr'
This commit addresses the test failures reported in issue #156
on FreeBSD platform.
1. Fix POSIX semaphore naming for FreeBSD compatibility
- FreeBSD requires semaphore names to start with "/"
- Add "_sem" suffix to avoid namespace conflicts with shm
- Store semaphore name separately for proper cleanup
- This fixes all 24 semaphore test failures
2. Fix robust mutex EOWNERDEAD handling
- When pthread_mutex_lock returns EOWNERDEAD, the lock is
already acquired by the calling thread
- After calling pthread_mutex_consistent(), we should return
success immediately, not unlock and retry
- Previous behavior caused issues with FreeBSD's libthr robust
mutex list management, leading to fatal errors
- This fixes the random crashes in MutexTest
Technical details:
- EOWNERDEAD indicates the previous lock owner died while holding
the lock, but the current thread has successfully acquired it
- pthread_mutex_consistent() restores the mutex to a consistent state
- The Linux implementation worked differently, but the new approach
is more correct according to POSIX semantics and works on both
Linux and FreeBSD
Fixes#156
- Remove useless 'ii->size_ = ii->size_;' statement at line 140
- The user-requested size is already set in acquire() function
- Simplify else branch to just a comment for clarity
- No functional change, just code cleanup
Problem:
- Reference counting tests fail on Windows (ReleaseMemory, ReferenceCount,
SubtractReference, HandleRef, HandleSubRef)
- get_ref() and sub_ref() were stub implementations returning 0/doing nothing
- CreateFileMapping HANDLE lacks built-in reference counting mechanism
Solution:
- Implement reference counting using std::atomic<std::int32_t> stored at
the end of shared memory (same strategy as POSIX version)
- Add calc_size() helper to allocate extra space for atomic counter
- Add acc_of() helper to access the atomic counter at the end of memory
- Modify acquire() to allocate calc_size(size) instead of size
- Modify get_mem() to initialize counter to 1 on first mapping
- Modify release() to decrement counter and return ref count before decrement
- Implement get_ref() to return current reference count
- Implement sub_ref() to atomically decrement reference count
- Convert file from Windows (CRLF) to Unix (LF) line endings for consistency
Key Implementation Details:
1. Reference counter stored at end of shared memory (aligned to info_t)
2. First get_mem() call: fetch_add(1) initializes counter to 1
3. release() returns ref count before decrement (for semantics compatibility)
4. Memory layout: [user data][padding][atomic<int32_t> counter]
5. Uses memory_order_acquire/release/acq_rel for proper synchronization
This makes Windows implementation match POSIX behavior and ensures all
reference counting tests pass on Windows platform.
Problem:
- Both linux/get_wait_time.h and posix/get_wait_time.h define inline functions
make_timespec() and calc_wait_time() in namespace ipc::detail
- On Linux, semaphore uses posix implementation, but may include both headers
- This causes ODR (One Definition Rule) violation - undefined behavior
- Different inline function definitions with same name violates C++ standard
- Manifested as test failures in SemaphoreTest::WaitTimeout
Solution:
- Add platform-specific namespace layer between ipc and detail:
- linux/get_wait_time.h: ipc::linux::detail::make_timespec()
- posix/get_wait_time.h: ipc::posix::detail::make_timespec()
- Update all call sites to use fully qualified names:
- linux/condition.h: linux::detail::make_timespec()
- linux/mutex.h: linux::detail::make_timespec() (2 places)
- posix/condition.h: posix::detail::make_timespec()
- posix/mutex.h: posix::detail::make_timespec() (2 places)
- posix/semaphore_impl.h: posix::detail::make_timespec()
This ensures each platform's implementation is uniquely named, preventing
ODR violations and ensuring correct function resolution at compile time.
Header changes (include/libipc/buffer.h):
- Rename: additional → mem_to_free (better semantic name)
- Add documentation comments explaining the parameter's purpose
- Clarifies that mem_to_free is passed to destructor instead of p
- Use case: when data pointer is offset into a larger allocation
Implementation changes (src/libipc/buffer.cpp):
- Update parameter name in constructor implementation
- No logic changes, just naming improvement
Test changes (test/test_buffer.cpp):
- Fix TEST_F(BufferTest, ConstructorWithMemToFree)
- Previous test caused crash: passed stack variable address to destructor
- New test correctly demonstrates the parameter's purpose:
* Allocate 100-byte block
* Use offset portion (bytes 25-75) as data
* Destructor receives original block pointer for proper cleanup
- Prevents double-free and invalid free errors
Semantic explanation:
buffer(data_ptr, size, destructor, mem_to_free)
On destruction:
destructor(mem_to_free ? mem_to_free : data_ptr, size)
This allows:
char* block = new char[100];
char* data = block + 25;
buffer buf(data, 50, my_free, block); // Frees 'block', not 'data'
- Add IPC_OS_FREEBSD_ platform detection macro
- Enable FreeBSD to use POSIX pthread implementation (shared with QNX)
- Update all conditional compilation directives to include FreeBSD
- Update README to reflect FreeBSD platform support
FreeBSD uses the existing POSIX implementation which supports:
- Process-shared mutexes (PTHREAD_PROCESS_SHARED)
- Robust mutexes (PTHREAD_MUTEX_ROBUST)
- Timed lock operations
- POSIX shared memory
This is a minimal change that reuses the mature POSIX implementation
already proven by QNX platform support.
