cpplog

minimal header-only logging for C++17

drop one header into your project and get colored, leveled, formatted logging.

#include "cpplog/log.hpp"

cpplog::info("server started on port {}", 8080);
cpplog::warn("memory at {}%", 87);
cpplog::error("connection failed: {}", "timeout");
cpplog::debug("loaded {} entries", count);

output in terminal (color-coded by level):

[INFO ] 14:02:11 server started on port 8080
[WARN ] 14:02:11 memory at 87%
[ERROR] 14:02:11 connection failed: timeout
[DEBUG] 14:02:11 loaded 42 entries

install

copy include/cpplog/log.hpp into your project.

or with CMake FetchContent:

include(FetchContent)
FetchContent_Declare(cpplog
    GIT_REPOSITORY https://github.com/ligumas/cpplog.git
    GIT_TAG        main
)
FetchContent_MakeAvailable(cpplog)
target_link_libraries(your_target cpplog)

usage

#include "cpplog/log.hpp"

cpplog::debug("x = {}", x);
cpplog::info("ready");
cpplog::warn("high load: {}%", load);
cpplog::error("failed: {}", msg);

cpplog::set_level(cpplog::Level::WARN);  // filter below WARN
cpplog::set_color(false);                // disable ANSI (e.g. piped output)
cpplog::set_time(false);                 // drop timestamp (log collector adds its own)
cpplog::set_file("app.log");             // also write to file

use the CPPLOG_* macros when you want file and line in the output:

CPPLOG_INFO("loading {} samples", n);
CPPLOG_WARN("slow response: {}ms", ms);
CPPLOG_ERROR("disk full");

[INFO ] 14:02:11 main.cpp:12 loading 500 samples
[WARN ] 14:02:11 server.cpp:87 slow response: 340ms
[ERROR] 14:02:11 disk.cpp:203 disk full

set_time(false) still keeps file:line when using CPPLOG_* macros — you get location without the clock.

features

• single header, zero dependencies
• C++17, Linux/Windows/macOS
• {} placeholder formatting
• log levels: DEBUG INFO WARN ERROR
• colored terminal output (ANSI)
• optional file output
• optional timestamp (set_time(false) for structured log collectors)
• thread-safe
• CPPLOG_* macros for file:line source location

build / test

cmake -B build && cmake --build build
./build/tests

License: MIT