Add C++ fmt-style logging frontend (`ulog_fmt`) by Copilot · Pull Request #4 · shawnfeng0/ulog

Copilot · 2026-02-21T09:39:49Z

Adds a header-only C++ logging frontend that accepts {}-style format strings (fmt interface) with a spdlog-style class-based API, automatic source location capture without macros, and bundled fmt headers to avoid any network downloads or symbol conflicts.

New files

include/ulog/ulog_fmt.h — Header-only C++ frontend in namespace ulog. Provides a Logger class with trace() / debug() / info() / warn() / error() / fatal() / raw() methods, plus free functions using a default global logger. Source location (file, line, function) is captured automatically at the call site via __builtin_FILE() / __builtin_LINE() / __builtin_FUNCTION() default constructor parameters — no macros required. Fully self-contained C++ implementation; does not call any C-API functions (logger_log_with_header, logger_raw, etc.).
cmake/fmt.cmake — Uses the fmt headers bundled in third_party/fmt/ (header-only mode, FMT_HEADER_ONLY=1). Falls back to a system find_package(fmt) if the bundled directory is absent. No network downloads.
third_party/fmt/include/fmt/ — fmt 9.1.0 headers bundled directly in the repository.
tests/ulog_fmt_test.cc — gtest tests covering all log levels, level filtering, automatic source location capture, format specifiers, raw output, and free functions. Compiled as part of the existing ulog_unit_test target.

Modified files

CMakeLists.txt — Removed ULOG_BUILD_FMT option; ulog_fmt interface target is always compiled unconditionally.
tests/CMakeLists.txt — ulog_fmt_test.cc added to ulog_unit_test (gtest) target; no separate executable.

Usage

#include "ulog/ulog_fmt.h"

// Free functions using the global default logger
ulog::info("PI = {:.3f}", 3.14159);
ulog::debug("int={} str={} hex={:#x}", 42, "hello", 255);

// Dedicated logger instance
ulog::Logger my_logger;
my_logger.set_output_callback(my_cb);
my_logger.warn("x={:.2f}", value);

target_link_libraries(my_target PRIVATE ulog_fmt)

Original prompt

添加一个C++版本的日志前端，使用fmt库的接口，如果cpp库不支持，就把独立的fmt库依赖进来，并且使用独立的命名空间，不要和原始的fmt库有符号重定义

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

Co-authored-by: shawnfeng0 <23150404+shawnfeng0@users.noreply.github.com>

shawnfeng0 · 2026-02-21T10:11:35Z

c++版本的接口不要再使用宏接口，可以参考spdlog的实现

shawnfeng0 · 2026-02-21T11:33:10Z

CMakeLists.txt

 option(ULOG_BUILD_EXAMPLES "Build examples" OFF)
 option(ULOG_BUILD_TESTS "Build tests" OFF)
 option(ULOG_BUILD_TOOLS "Build tools" ON)
+option(ULOG_BUILD_FMT "Build C++ fmt frontend (ulog_fmt target)" ON)


默认编译即可，不需要添加cmake选项

已在 2e1a699 中移除 ULOG_BUILD_FMT 选项，ulog_fmt 目标默认直接编译，无需判断。

shawnfeng0 · 2026-02-21T11:33:52Z

CMakeLists.txt

    include(cmake/zstd.cmake)
 endif ()

+if (ULOG_BUILD_FMT OR ULOG_BUILD_TESTS)


默认编译即可，无需判断

已在 2e1a699 中移除条件判断，include(cmake/fmt.cmake) 和 ulog_fmt 目标现在无条件编译。

shawnfeng0 · 2026-02-21T11:35:05Z

include/ulog/ulog_fmt.h

+// Step 3: convenience macros mirroring the LOGGER_* / LOGGER_LOCAL_* set
+// ---------------------------------------------------------------------------
+
+#define LOGGER_FMT_LOCAL_TRACE(logger, ...)                               \


cpp版本不要再使用宏了

已在 2e1a699 中完全移除所有宏，改用 Logger 类方法和 ulog::info(...) 等自由函数。

shawnfeng0 · 2026-02-21T11:36:03Z

tests/CMakeLists.txt

 add_test(ulog_unit_test ulog_unit_test)
+
+# C++ fmt frontend test
+add_executable(ulog_fmt_test ulog_fmt_test.cc)


跟随单元测试一起编译即可，不用单独编译fmt的测试

已在 2e1a699 中将 ulog_fmt_test.cc 合并进 ulog_unit_test 目标（使用 gtest），移除了单独的 ulog_fmt_test 可执行文件和测试条目。

shawnfeng0 · 2026-02-21T11:37:37Z

include/ulog/ulog_fmt.h

+#else
+  auto msg = fmt::format(fmt_str, std::forward<Args>(args)...);
+#endif
+  logger_log_with_header(logger, level, file, func, line, true, true, "%s",


cpp版本不要使用任何原有c语言版本的接口，以后会逐步淘汰c版本接口

已在 2e1a699 中完全重写 ulog_fmt.h：Logger 类不再调用任何 C 语言接口（logger_log_with_header、logger_raw 等），时间戳、PID/TID、颜色、等级标记、源码位置等所有格式化逻辑均用 C++ + fmt 独立实现。

shawnfeng0 · 2026-02-21T11:38:53Z

cmake/fmt.cmake

+    target_link_libraries(ulog_fmt_dep INTERFACE fmt::fmt)
+    message(STATUS "ulog_fmt: using system {fmt} ${fmt_VERSION}")
+else ()
+    include(FetchContent)


可以提前把fmt的源码拷贝到源码目录，不要再执行下载流程

已在 2e1a699 中将 fmt 9.1.0 的头文件拷贝至 third_party/fmt/include/fmt/，cmake/fmt.cmake 优先使用该本地目录（header-only 模式），不再执行下载流程。

…tion, tests with unit tests Co-authored-by: shawnfeng0 <23150404+shawnfeng0@users.noreply.github.com>

Copilot · 2026-02-21T11:53:55Z

c++版本的接口不要再使用宏接口，可以参考spdlog的实现

已重写为 spdlog 风格的 C++ 接口（commit 2e1a699）：

Logger 类提供 trace() / debug() / info() / warn() / error() / fatal() / raw() 方法
全局 ulog::get_default_logger() 和自由函数 ulog::info(...) 等，与 spdlog 的用法一致
不再有任何宏，源码位置（文件/行号/函数名）通过 __builtin_FILE() / __builtin_LINE() / __builtin_FUNCTION() 作为构造函数默认参数在调用点自动捕获，无需宏即可获取完整位置信息
不调用任何 C 语言接口（logger_log_with_header 等），日志格式化和输出完全在 C++ 中实现

Initial plan

8d3afc9

Copilot AI assigned Copilot and shawnfeng0 Feb 21, 2026

Copilot started work on behalf of shawnfeng0 February 21, 2026 09:40 View session

Copilot AI and others added 2 commits February 21, 2026 09:53

Add C++ fmt-style logging frontend (ulog_fmt)

9cfef01

Co-authored-by: shawnfeng0 <23150404+shawnfeng0@users.noreply.github.com>

Remove CodeQL artifacts from tracking, add to .gitignore

fa496de

Co-authored-by: shawnfeng0 <23150404+shawnfeng0@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Add C++ logging frontend with fmt library integration~~ Add C++ fmt-style logging frontend (ulog_fmt) Feb 21, 2026

Copilot AI requested a review from shawnfeng0 February 21, 2026 09:55

Copilot finished work on behalf of shawnfeng0 February 21, 2026 09:55

shawnfeng0 requested changes Feb 21, 2026

View reviewed changes

Copilot started work on behalf of shawnfeng0 February 21, 2026 11:39 View session

Revise C++ fmt frontend: no macros, no C API, bundle fmt, no cmake op…

2e1a699

…tion, tests with unit tests Co-authored-by: shawnfeng0 <23150404+shawnfeng0@users.noreply.github.com>

Copilot AI requested a review from shawnfeng0 February 21, 2026 11:54

Copilot finished work on behalf of shawnfeng0 February 21, 2026 11:54

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Copilot AI commented Feb 21, 2026 •

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