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2593213d9c
Problem: Tests fail on the second run on FreeBSD with ShmTest.RemoveByName failing.
After the first test run completes, subsequent runs fail because shared memory
objects are not properly removed.
Root cause: FreeBSD's shm_unlink() is stricter than Linux about POSIX compliance.
The remove(char const * name) function was calling shm_unlink() without the '/'
prefix, while acquire() was using '/'+name format. This inconsistency caused:
- Linux: Silently tolerates both /name and name formats
- FreeBSD: Strictly requires /name format, shm_unlink("name") fails
When shm_unlink() fails to remove the shared memory object:
1. First test run creates /remove_by_name_test_1
2. Test calls shm::remove("remove_by_name_test_1")
3. shm_unlink("remove_by_name_test_1") fails on FreeBSD (missing '/')
4. Shared memory object remains in the system
5. Second test run tries to reuse the same name -> conflict -> test fails
Solution:
1. Fix remove(char const * name) to prepend '/' to the name for consistency
with acquire() function, ensuring POSIX compliance
2. Add error checking for all shm_unlink() calls to log failures with errno
This ensures proper cleanup on FreeBSD and maintains compatibility with Linux.
Changes:
- Modified remove(char const * name) to use '/'+name format
- Added error logging for all three shm_unlink() calls
- Now consistent with POSIX requirement: shared memory names must be /somename
Tested on FreeBSD 15: Multiple consecutive test runs now pass without failures.
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|---|---|---|
| .github/workflows | ||
| 3rdparty | ||
| demo | ||
| include/libipc | ||
| src | ||
| test | ||
| .gitignore | ||
| CMakeLists.txt | ||
| LICENSE | ||
| performance.xlsx | ||
| README.md | ||
cpp-ipc (libipc) - C++ IPC Library
A high-performance inter-process communication library using shared memory on Linux/Windows/FreeBSD.
- Compilers with C++17 support are recommended (msvc-2017/gcc-7/clang-4)
- No other dependencies except STL.
- Only lock-free or lightweight spin-lock is used.
- Circular array is used as the underline data structure.
ipc::routesupports single write and multiple read.ipc::channelsupports multiple read and write. (Note: currently, a channel supports up to 32 receivers, but there is no such a limit for the sender.)- Broadcasting is used by default, but user can choose any read/ write combinations.
- No long time blind wait. (Semaphore will be used after a certain number of retries.)
- Vcpkg way of installation is supported. E.g.
vcpkg install cpp-ipc
Usage
See: Wiki
Performance
| Environment | Value |
|---|---|
| Device | Lenovo ThinkPad T450 |
| CPU | Intel® Core™ i5-4300U @ 2.5 GHz |
| RAM | 16 GB |
| OS | Windows 7 Ultimate x64 |
| Compiler | MSVC 2017 15.9.4 |
Unit & benchmark tests: test
Performance data: performance.xlsx
Reference
- Lock-Free Data Structures | Dr Dobb's
- Yet another implementation of a lock-free circular array queue | CodeProject
- Lock-Free 编程 | 匠心十年 - 博客园
- 无锁队列的实现 | 酷 壳 - CoolShell
- Implementing Condition Variables with Semaphores
使用共享内存的跨平台（Linux/Windows/FreeBSD，x86/x64/ARM）高性能IPC通讯库
- 推荐支持C++17的编译器（msvc-2017/gcc-7/clang-4）
- 除STL外，无其他依赖
- 无锁（lock-free）或轻量级spin-lock
- 底层数据结构为循环数组（circular array）
ipc::route支持单写多读，ipc::channel支持多写多读【注意：目前同一条通道最多支持32个receiver，sender无限制】- 默认采用广播模式收发数据，支持用户任意选择读写方案
- 不会长时间忙等（重试一定次数后会使用信号量进行等待），支持超时
- 支持Vcpkg方式安装，如
vcpkg install cpp-ipc
使用方法
详见：Wiki
性能
| 环境 | 值 |
|---|---|
| 设备 | 联想 ThinkPad T450 |
| CPU | 英特尔® Core™ i5-4300U @ 2.5 GHz |
| 内存 | 16 GB |
| 操作系统 | Windows 7 Ultimate x64 |
| 编译器 | MSVC 2017 15.9.4 |
单元测试和Benchmark测试: test
性能数据: performance.xlsx