Remove the fileapi.h include in os-inl.h (#3444)

* Replaced fileapi.h include with windows.h, as instructed in https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-flushfilebuffers
Otherwise this causes compilation error on older sdks.

* Removed the fileapi.h include entirely, since windows.h is already included before

---------

Co-authored-by: MasonAngelio <MasonAngelio>

.github/workflows/coverity_scan.yml

@@ -1,6 +1,6 @@
 name: coverity-linux
 
-on: [pull_request]
+on: [push, pull_request]
 
 permissions:
   contents: read
@@ -35,6 +35,7 @@ jobs:
         run: |
           tar czf cov-int.tgz cov-int
           response=$(curl --silent --show-error --fail \
+            --form email="${{ secrets.EMAIL }}" \
             --form token="${{ secrets.COVERITY_TOKEN }}" \
             --form file=@cov-int.tgz \
             --form version="GitHub PR #${{ github.event.pull_request.number }}" \

.github/workflows/linux.yml

@@ -18,9 +18,8 @@ jobs:
       fail-fast: false
       matrix:
         config:
-          - { compiler: gcc, version: 7, build_type: Release, cppstd: 11 }
-          - { compiler: gcc, version: 9, build_type: Release, cppstd: 17 }
-          - { compiler: gcc, version: 11, build_type: Debug, cppstd: 20 }
+          - { compiler: gcc, version: 9, build_type: Release, cppstd: 11 }
+          - { compiler: gcc, version: 11, build_type: Debug, cppstd: 17 }
           - { compiler: gcc, version: 12, build_type: Release, cppstd: 20 }
           - { compiler: gcc, version: 12, build_type: Debug, cppstd: 20, asan: ON }
           - { compiler: clang, version: 12, build_type: Debug, cppstd: 17 }

.github/workflows/windows.yml

@@ -75,74 +75,5 @@ jobs:
         run: |
           build\tests\${{ matrix.config.BUILD_TYPE }}\spdlog-utests.exe
 
-  # -----------------------------------------------------------------------
-  # MSVC 2019 build matrix
-  # -----------------------------------------------------------------------
-  build_2019:
-    runs-on: windows-2019
-    strategy:
-      fail-fast: true
-      matrix:
-        config:
-          - GENERATOR: "Visual Studio 16 2019"
-            BUILD_TYPE: Release
-            BUILD_SHARED: 'ON'
-            FATAL_ERRORS: 'ON'
-            WCHAR: 'OFF'
-            WCHAR_FILES: 'OFF'
-            BUILD_EXAMPLE: 'ON'
-            USE_STD_FORMAT: 'OFF'
-            CXX_STANDARD: 17
-          - GENERATOR: "Visual Studio 16 2019"
-            BUILD_TYPE: Release
-            BUILD_SHARED: 'ON'
-            FATAL_ERRORS: 'ON'
-            WCHAR: 'OFF'
-            WCHAR_FILES: 'OFF'
-            BUILD_EXAMPLE: 'ON'
-            USE_STD_FORMAT: 'OFF'
-            CXX_STANDARD: 14
-          - GENERATOR: "Visual Studio 16 2019"
-            BUILD_TYPE: Release
-            BUILD_SHARED: 'ON'
-            FATAL_ERRORS: 'ON'
-            WCHAR: 'OFF'
-            WCHAR_FILES: 'OFF'
-            BUILD_EXAMPLE: 'ON'
-            USE_STD_FORMAT: 'OFF'
-            CXX_STANDARD: 11
 
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v4
   
-      - name: CMake ${{ matrix.config.GENERATOR }} CXX=${{matrix.config.CXX_STANDARD}} WCHAR=${{matrix.config.WCHAR_FILES}} STD_FORMAT=${{matrix.config.USE_STD_FORMAT}}
-        shell: pwsh
-        run: |
-          mkdir build
-          cd build
-          cmake -G "${{ matrix.config.GENERATOR }}"  -A x64 `
-            -D CMAKE_BUILD_TYPE=${{ matrix.config.BUILD_TYPE }} `
-            -D BUILD_SHARED_LIBS=${{ matrix.config.BUILD_SHARED }} `
-            -D SPDLOG_WCHAR_SUPPORT=${{ matrix.config.WCHAR }} `
-            -D SPDLOG_WCHAR_FILENAMES=${{ matrix.config.WCHAR_FILES }} `
-            -D SPDLOG_BUILD_EXAMPLE=${{ matrix.config.BUILD_EXAMPLE }} `
-            -D SPDLOG_BUILD_EXAMPLE_HO=${{ matrix.config.BUILD_EXAMPLE }} `
-            -D SPDLOG_BUILD_TESTS=ON `
-            -D SPDLOG_BUILD_TESTS_HO=OFF `
-            -D SPDLOG_BUILD_WARNINGS=${{ matrix.config.FATAL_ERRORS }} `
-            -D SPDLOG_USE_STD_FORMAT=${{ matrix.config.USE_STD_FORMAT }} `
-            -D CMAKE_CXX_STANDARD=${{ matrix.config.CXX_STANDARD }} ..
-
-      - name: Build
-        shell: pwsh
-        run: |
-          cd build
-          cmake --build  . --parallel --config ${{ matrix.config.BUILD_TYPE }}
-
-      - name: Run Tests
-        shell: pwsh
-        env:
-          PATH: ${{ env.PATH }};${{ github.workspace }}\build\_deps\catch2-build\src\${{ matrix.config.BUILD_TYPE }};${{ github.workspace }}\build\${{ matrix.config.BUILD_TYPE }}
-        run: |
-          build\tests\${{ matrix.config.BUILD_TYPE }}\spdlog-utests.exe

CMakeLists.txt

@@ -62,6 +62,9 @@ option(SPDLOG_ENABLE_PCH "Build static or shared library using precompiled heade
 # build position independent code
 option(SPDLOG_BUILD_PIC "Build position independent code (-fPIC)" OFF)
 
+# debug build postfix
+set(SPDLOG_DEBUG_POSTFIX "d" CACHE STRING "Filename postfix for libraries in debug builds")
+
 # example options
 option(SPDLOG_BUILD_EXAMPLE "Build example" ${SPDLOG_MASTER_PROJECT})
 option(SPDLOG_BUILD_EXAMPLE_HO "Build header only example" OFF)
@@ -191,7 +194,7 @@ spdlog_enable_warnings(spdlog)
 
 set_target_properties(spdlog PROPERTIES VERSION ${SPDLOG_VERSION} SOVERSION
                                                                   ${SPDLOG_VERSION_MAJOR}.${SPDLOG_VERSION_MINOR})
-set_target_properties(spdlog PROPERTIES DEBUG_POSTFIX d)
+set_target_properties(spdlog PROPERTIES DEBUG_POSTFIX ${SPDLOG_DEBUG_POSTFIX})
 
 if(COMMAND target_precompile_headers AND SPDLOG_ENABLE_PCH)
     configure_file(${CMAKE_CURRENT_SOURCE_DIR}/cmake/pch.h.in ${PROJECT_BINARY_DIR}/spdlog_pch.h @ONLY)

README.md

@@ -80,7 +80,7 @@ int main()
     spdlog::info("Positional args are {1} {0}..", "too", "supported");
     spdlog::info("{:<30}", "left aligned");
     
-    spdlog::set_level(spdlog::level::debug); // Set global log level to debug
+    spdlog::set_level(spdlog::level::debug); // Set *global* log level to debug
     spdlog::debug("This message should be displayed..");    
     
     // change log pattern
@@ -241,6 +241,29 @@ void multi_sink_example()
 }
 ```
 
+---
+#### Register several loggers - change global level
+```c++
+
+// Creation of loggers. Set levels to all registered loggers. 
+void set_level_example()
+{
+    auto logger1 = spdlog::basic_logger_mt("logger1", "logs/logger1.txt");
+    auto logger2 = spdlog::basic_logger_mt("logger2", "logs/logger2.txt");
+
+    spdlog::set_default_logger(logger2);
+    spdlog::default_logger()->set_level(spdlog::level::trace); // set level for the default logger (logger2) to trace
+
+    spdlog::trace("trace message to the logger2 (specified as default)");
+
+    spdlog::set_level(spdlog::level::off) // (sic!) set level for *all* registered loggers to off (disable)
+  
+    logger1.warn("warn message will not appear because the level set to off");
+    logger2.warn("warn message will not appear because the level set to off");
+    spdlog::warn("warn message will not appear because the level set to off");
+}
+```
+
 ---
 #### User-defined callbacks about log events
 ```c++

include/spdlog/cfg/helpers-inl.h

@@ -71,7 +71,7 @@ inline std::unordered_map<std::string, std::string> extract_key_vals_(const std:
 }
 
 SPDLOG_INLINE void load_levels(const std::string &input) {
-    if (input.empty() || input.size() > 512) {
+    if (input.empty() || input.size() >= 32768) {
         return;
     }
 

include/spdlog/details/os-inl.h

@@ -23,7 +23,6 @@
 
 #ifdef _WIN32
     #include <spdlog/details/windows_include.h>
-    #include <fileapi.h>  // for FlushFileBuffers
     #include <io.h>       // for _get_osfhandle, _isatty, _fileno
     #include <process.h>  // for _get_pid
 
@@ -563,21 +562,21 @@ SPDLOG_INLINE filename_t dir_name(const filename_t &path) {
     return pos != filename_t::npos ? path.substr(0, pos) : filename_t{};
 }
 
+#ifdef _MSC_VER
+    #pragma warning(push)
+    #pragma warning(disable : 4996)
+#endif  // _MSC_VER
 std::string SPDLOG_INLINE getenv(const char *field) {
-#if defined(_MSC_VER)
-    #if defined(__cplusplus_winrt)
+#if defined(_MSC_VER) && defined(__cplusplus_winrt)
     return std::string{};  // not supported under uwp
-    #else
-    size_t len = 0;
-    char buf[128];
-    bool ok = ::getenv_s(&len, buf, sizeof(buf), field) == 0;
-    return ok ? buf : std::string{};
-    #endif
-#else  // revert to getenv
-    char *buf = ::getenv(field);
+#else
+    char *buf = std::getenv(field);
     return buf ? buf : std::string{};
 #endif
 }
+#ifdef _MSC_VER
+    #pragma warning(pop)
+#endif  // _MSC_VER
 
 // Do fsync by FILE handlerpointer
 // Return true on success

include/spdlog/details/tcp_client-windows.h

@@ -58,8 +58,81 @@ public:
 
     SOCKET fd() const { return socket_; }
     
+    int connect_socket_with_timeout(SOCKET sockfd,
+                                    const struct sockaddr *addr,
+                                    int addrlen,
+                                    const timeval &tv) {
+        // If no timeout requested, do a normal blocking connect.
+        if (tv.tv_sec == 0 && tv.tv_usec == 0) {
+            int rv = ::connect(sockfd, addr, addrlen);
+            if (rv == SOCKET_ERROR && WSAGetLastError() == WSAEISCONN) {
+                return 0;
+            }
+            return rv;
+        }
+
+        // Switch to non‐blocking mode
+        u_long mode = 1UL;
+        if (::ioctlsocket(sockfd, FIONBIO, &mode) == SOCKET_ERROR) {
+            return SOCKET_ERROR;
+        }
+
+        int rv = ::connect(sockfd, addr, addrlen);
+        int last_error = WSAGetLastError();
+        if (rv == 0 || last_error == WSAEISCONN) {
+            mode = 0UL;
+            if (::ioctlsocket(sockfd, FIONBIO, &mode) == SOCKET_ERROR) {
+                return SOCKET_ERROR;
+            }
+            return 0;
+        }
+        if (last_error != WSAEWOULDBLOCK) {
+            // Real error
+            mode = 0UL;
+            if (::ioctlsocket(sockfd, FIONBIO, &mode)) {
+                return SOCKET_ERROR;
+            }
+            return SOCKET_ERROR;
+        }
+
+        // Wait until socket is writable or timeout expires
+        fd_set wfds;
+        FD_ZERO(&wfds);
+        FD_SET(sockfd, &wfds);
+
+        rv = ::select(0, nullptr, &wfds, nullptr, const_cast<timeval *>(&tv));
+
+        // Restore blocking mode regardless of select result
+        mode = 0UL;
+        if (::ioctlsocket(sockfd, FIONBIO, &mode) == SOCKET_ERROR) {
+            return SOCKET_ERROR;
+        }
+
+        if (rv == 0) {
+            WSASetLastError(WSAETIMEDOUT);
+            return SOCKET_ERROR;
+        }
+        if (rv == SOCKET_ERROR) {
+            return SOCKET_ERROR;
+        }
+
+        int so_error = 0;
+        int len = sizeof(so_error);
+        if (::getsockopt(sockfd, SOL_SOCKET, SO_ERROR, reinterpret_cast<char *>(&so_error), &len) ==
+            SOCKET_ERROR) {
+            return SOCKET_ERROR;
+        }
+        if (so_error != 0 && so_error != WSAEISCONN) {
+            // connection failed
+            WSASetLastError(so_error);
+            return SOCKET_ERROR;
+        }
+
+        return 0;  // success
+    }
+
     // try to connect or throw on failure
-    void connect(const std::string &host, int port) {
+    void connect(const std::string &host, int port, int timeout_ms = 0) {
         if (is_connected()) {
             close();
         }
@@ -71,6 +144,10 @@ public:
         hints.ai_flags = AI_NUMERICSERV;  // port passed as as numeric value
         hints.ai_protocol = 0;
 
+        timeval tv;
+        tv.tv_sec = timeout_ms / 1000;
+        tv.tv_usec = (timeout_ms % 1000) * 1000;
+
         auto port_str = std::to_string(port);
         struct addrinfo *addrinfo_result;
         auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
@@ -82,7 +159,6 @@ public:
         }
 
         // Try each address until we successfully connect(2).
-
         for (auto *rp = addrinfo_result; rp != nullptr; rp = rp->ai_next) {
             socket_ = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
             if (socket_ == INVALID_SOCKET) {
@@ -90,18 +166,24 @@ public:
                 WSACleanup();
                 continue;
             }
-            if (::connect(socket_, rp->ai_addr, (int)rp->ai_addrlen) == 0) {
+            if (connect_socket_with_timeout(socket_, rp->ai_addr, (int)rp->ai_addrlen, tv) == 0) {
+                last_error = 0;
                 break;
-            } else {
-                last_error = ::WSAGetLastError();
-                close();
             }
+            last_error = WSAGetLastError();
+            ::closesocket(socket_);
+            socket_ = INVALID_SOCKET;
         }
         ::freeaddrinfo(addrinfo_result);
         if (socket_ == INVALID_SOCKET) {
             WSACleanup();
             throw_winsock_error_("connect failed", last_error);
         }
+        if (timeout_ms > 0) {
+            DWORD tv = static_cast<DWORD>(timeout_ms);
+            ::setsockopt(socket_, SOL_SOCKET, SO_RCVTIMEO, (const char *)&tv, sizeof(tv));
+            ::setsockopt(socket_, SOL_SOCKET, SO_SNDTIMEO, (const char *)&tv, sizeof(tv));
+        }
 
         // set TCP_NODELAY
         int enable_flag = 1;

include/spdlog/details/tcp_client.h

@@ -39,8 +39,72 @@ public:
 
     ~tcp_client() { close(); }
 
+    int connect_socket_with_timeout(int sockfd,
+                                    const struct sockaddr *addr,
+                                    socklen_t addrlen,
+                                    const timeval &tv) {
+        // Blocking connect if timeout is zero
+        if (tv.tv_sec == 0 && tv.tv_usec == 0) {
+            int rv = ::connect(sockfd, addr, addrlen);
+            if (rv < 0 && errno == EISCONN) {
+                // already connected, treat as success
+                return 0;
+            }
+            return rv;
+        }
+
+        // Non-blocking path
+        int orig_flags = ::fcntl(sockfd, F_GETFL, 0);
+        if (orig_flags < 0) {
+            return -1;
+        }
+        if (::fcntl(sockfd, F_SETFL, orig_flags | O_NONBLOCK) < 0) {
+            return -1;
+        }
+
+        int rv = ::connect(sockfd, addr, addrlen);
+        if (rv == 0 || (rv < 0 && errno == EISCONN)) {
+            // immediate connect or already connected
+            ::fcntl(sockfd, F_SETFL, orig_flags);
+            return 0;
+        }
+        if (errno != EINPROGRESS) {
+            ::fcntl(sockfd, F_SETFL, orig_flags);
+            return -1;
+        }
+
+        // wait for writability
+        fd_set wfds;
+        FD_ZERO(&wfds);
+        FD_SET(sockfd, &wfds);
+
+        struct timeval tv_copy = tv;
+        rv = ::select(sockfd + 1, nullptr, &wfds, nullptr, &tv_copy);
+        if (rv <= 0) {
+            // timeout or error
+            ::fcntl(sockfd, F_SETFL, orig_flags);
+            if (rv == 0) errno = ETIMEDOUT;
+            return -1;
+        }
+
+        // check socket error
+        int so_error = 0;
+        socklen_t len = sizeof(so_error);
+        if (::getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &so_error, &len) < 0) {
+            ::fcntl(sockfd, F_SETFL, orig_flags);
+            return -1;
+        }
+        ::fcntl(sockfd, F_SETFL, orig_flags);
+        if (so_error != 0 && so_error != EISCONN) {
+            errno = so_error;
+            return -1;
+        }
+
+        return 0;
+    }
+
     // try to connect or throw on failure
-    void connect(const std::string &host, int port) {
+    void connect(const std::string &host, int port, int timeout_ms = 0) {
         close();
         struct addrinfo hints {};
         memset(&hints, 0, sizeof(struct addrinfo));
@@ -49,6 +113,10 @@ public:
         hints.ai_flags = AI_NUMERICSERV;  // port passed as as numeric value
         hints.ai_protocol = 0;
 
+        struct timeval tv;
+        tv.tv_sec = timeout_ms / 1000;
+        tv.tv_usec = (timeout_ms % 1000) * 1000;
+
         auto port_str = std::to_string(port);
         struct addrinfo *addrinfo_result;
         auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
@@ -69,8 +137,9 @@ public:
                 last_errno = errno;
                 continue;
             }
-            rv = ::connect(socket_, rp->ai_addr, rp->ai_addrlen);
-            if (rv == 0) {
+            ::fcntl(socket_, F_SETFD, FD_CLOEXEC);
+            if (connect_socket_with_timeout(socket_, rp->ai_addr, rp->ai_addrlen, tv) == 0) {
+                last_errno = 0;
                 break;
             }
             last_errno = errno;
@@ -82,6 +151,12 @@ public:
             throw_spdlog_ex("::connect failed", last_errno);
         }
 
+        if (timeout_ms > 0) {
+            // Set timeouts for send and recv
+            ::setsockopt(socket_, SOL_SOCKET, SO_RCVTIMEO, (const char *)&tv, sizeof(tv));
+            ::setsockopt(socket_, SOL_SOCKET, SO_SNDTIMEO, (const char *)&tv, sizeof(tv));
+        }
+
         // set TCP_NODELAY
         int enable_flag = 1;
         ::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&enable_flag),

include/spdlog/fmt/fmt.h

@@ -20,11 +20,7 @@
     #ifndef FMT_USE_WINDOWS_H
         #define FMT_USE_WINDOWS_H 0
     #endif
-
-    #include <spdlog/fmt/bundled/base.h>
     #include <spdlog/fmt/bundled/format.h>
-
 #else  // SPDLOG_FMT_EXTERNAL is defined - use external fmtlib
-    #include <fmt/base.h>
     #include <fmt/format.h>
 #endif

include/spdlog/sinks/ansicolor_sink.h

@@ -40,7 +40,7 @@ public:
 
     void log(const details::log_msg &msg) override;
     void flush() override;
-    void set_pattern(const std::string &pattern) final override;
+    void set_pattern(const std::string &pattern) override;
     void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) override;
 
     // Formatting codes

include/spdlog/sinks/ringbuffer_sink.h

@@ -21,7 +21,11 @@ template <typename Mutex>
 class ringbuffer_sink final : public base_sink<Mutex> {
 public:
     explicit ringbuffer_sink(size_t n_items)
-        : q_{n_items} {}
+        : q_{n_items} {
+        if (n_items == 0) {
+            throw_spdlog_ex("ringbuffer_sink: n_items cannot be zero");
+        }
+    }
 
     std::vector<details::log_msg_buffer> last_raw(size_t lim = 0) {
         std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);

include/spdlog/sinks/tcp_sink.h

@@ -31,6 +31,7 @@ namespace sinks {
 struct tcp_sink_config {
     std::string server_host;
     int server_port;
+    int timeout_ms = 0; // The timeout for all 3 major socket operations that is connect, send, and recv
     bool lazy_connect = false;  // if true connect on first log call instead of on construction
 
     tcp_sink_config(std::string host, int port)
@@ -44,10 +45,22 @@ public:
     // connect to tcp host/port or throw if failed
     // host can be hostname or ip address
 
+    explicit tcp_sink(const std::string &host,
+                      int port,
+                      int timeout_ms = 0,
+                      bool lazy_connect = false)
+        : config_{host, port} {
+        config_.timeout_ms = timeout_ms;
+        config_.lazy_connect = lazy_connect;
+        if (!config_.lazy_connect) {
+            client_.connect(config_.server_host, config_.server_port, config_.timeout_ms);
+        }
+    }
+
     explicit tcp_sink(tcp_sink_config sink_config)
         : config_{std::move(sink_config)} {
         if (!config_.lazy_connect) {
-            this->client_.connect(config_.server_host, config_.server_port);
+            client_.connect(config_.server_host, config_.server_port, config_.timeout_ms);
         }
     }
 
@@ -58,7 +71,7 @@ protected:
         spdlog::memory_buf_t formatted;
         spdlog::sinks::base_sink<Mutex>::formatter_->format(msg, formatted);
         if (!client_.is_connected()) {
-            client_.connect(config_.server_host, config_.server_port);
+            client_.connect(config_.server_host, config_.server_port, config_.timeout_ms);
         }
         client_.send(formatted.data(), formatted.size());
     }

include/spdlog/sinks/wincolor_sink.h

@@ -31,10 +31,10 @@ public:
 
     // change the color for the given level
     void set_color(level::level_enum level, std::uint16_t color);
-    void log(const details::log_msg &msg) final override;
-    void flush() final override;
-    void set_pattern(const std::string &pattern) override final;
-    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) override final;
+    void log(const details::log_msg &msg) override;
+    void flush() override;
+    void set_pattern(const std::string &pattern) override;
+    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) override;
     void set_color_mode(color_mode mode);
 
 protected:

tests/CMakeLists.txt

@@ -49,7 +49,8 @@ set(SPDLOG_UTESTS_SOURCES
     test_time_point.cpp
     test_stopwatch.cpp
     test_circular_q.cpp
-    test_bin_to_hex.cpp)
+    test_bin_to_hex.cpp
+    test_ringbuffer.cpp)
 
 if(NOT SPDLOG_NO_EXCEPTIONS)
     list(APPEND SPDLOG_UTESTS_SOURCES test_errors.cpp)
@@ -74,7 +75,7 @@ function(spdlog_prepare_test test_target spdlog_lib)
     elseif(SPDLOG_SANITIZE_THREAD)
         spdlog_enable_thread_sanitizer(${test_target})
     endif()
-    add_test(NAME ${test_target} COMMAND ${test_target})
+    add_test(NAME ${test_target} COMMAND ${test_target} --order decl)
     set_tests_properties(${test_target} PROPERTIES RUN_SERIAL ON)
 endfunction()
 

tests/test_ringbuffer.cpp

@@ -0,0 +1,53 @@
+#include "includes.h"
+#include "spdlog/sinks/ringbuffer_sink.h"
+
+TEST_CASE("ringbuffer invalid size", "[ringbuffer]") {
+    REQUIRE_THROWS_AS(spdlog::sinks::ringbuffer_sink_mt(0), spdlog::spdlog_ex);
+}
+
+TEST_CASE("ringbuffer stores formatted messages", "[ringbuffer]") {
+    spdlog::sinks::ringbuffer_sink_st sink(3);
+    sink.set_pattern("%v");
+
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "msg1"});
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "msg2"});
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "msg3"});
+
+    auto formatted = sink.last_formatted();
+    REQUIRE(formatted.size() == 3);
+    using spdlog::details::os::default_eol;
+    REQUIRE(formatted[0] == spdlog::fmt_lib::format("msg1{}", default_eol));
+    REQUIRE(formatted[1] == spdlog::fmt_lib::format("msg2{}", default_eol));
+    REQUIRE(formatted[2] == spdlog::fmt_lib::format("msg3{}", default_eol));
+}
+
+TEST_CASE("ringbuffer overrun keeps last items", "[ringbuffer]") {
+    spdlog::sinks::ringbuffer_sink_st sink(2);
+    sink.set_pattern("%v");
+
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "first"});
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "second"});
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "third"});
+
+    auto formatted = sink.last_formatted();
+    REQUIRE(formatted.size() == 2);
+    using spdlog::details::os::default_eol;
+    REQUIRE(formatted[0] == spdlog::fmt_lib::format("second{}", default_eol));
+    REQUIRE(formatted[1] == spdlog::fmt_lib::format("third{}", default_eol));
+}
+
+TEST_CASE("ringbuffer retrieval limit", "[ringbuffer]") {
+    spdlog::sinks::ringbuffer_sink_st sink(3);
+    sink.set_pattern("%v");
+
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "A"});
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "B"});
+    sink.log(spdlog::details::log_msg{"test", spdlog::level::info, "C"});
+
+    auto formatted = sink.last_formatted(2);
+    REQUIRE(formatted.size() == 2);
+    using spdlog::details::os::default_eol;
+    REQUIRE(formatted[0] == spdlog::fmt_lib::format("B{}", default_eol));
+    REQUIRE(formatted[1] == spdlog::fmt_lib::format("C{}", default_eol));
+}
+