initial commit, 4.5 stable

thirdparty/sdl/SDL_log.c

@@ -0,0 +1,805 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_internal.h"
+
+#if defined(SDL_PLATFORM_WINDOWS)
+#include "core/windows/SDL_windows.h"
+#endif
+
+// Simple log messages in SDL
+
+#include "SDL_log_c.h"
+
+#ifdef HAVE_STDIO_H
+#include <stdio.h>
+#endif
+
+#ifdef SDL_PLATFORM_ANDROID
+#include <android/log.h>
+#endif
+
+#include "stdlib/SDL_vacopy.h"
+
+// The size of the stack buffer to use for rendering log messages.
+#define SDL_MAX_LOG_MESSAGE_STACK 256
+
+#define DEFAULT_CATEGORY -1
+
+typedef struct SDL_LogLevel
+{
+    int category;
+    SDL_LogPriority priority;
+    struct SDL_LogLevel *next;
+} SDL_LogLevel;
+
+
+// The default log output function
+static void SDLCALL SDL_LogOutput(void *userdata, int category, SDL_LogPriority priority, const char *message);
+
+static void CleanupLogPriorities(void);
+static void CleanupLogPrefixes(void);
+
+static SDL_InitState SDL_log_init;
+static SDL_Mutex *SDL_log_lock;
+static SDL_Mutex *SDL_log_function_lock;
+static SDL_LogLevel *SDL_loglevels SDL_GUARDED_BY(SDL_log_lock);
+static SDL_LogPriority SDL_log_priorities[SDL_LOG_CATEGORY_CUSTOM] SDL_GUARDED_BY(SDL_log_lock);
+static SDL_LogPriority SDL_log_default_priority SDL_GUARDED_BY(SDL_log_lock);
+static SDL_LogOutputFunction SDL_log_function SDL_GUARDED_BY(SDL_log_function_lock) = SDL_LogOutput;
+static void *SDL_log_userdata SDL_GUARDED_BY(SDL_log_function_lock) = NULL;
+
+#ifdef HAVE_GCC_DIAGNOSTIC_PRAGMA
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-variable"
+#endif
+
+// If this list changes, update the documentation for SDL_HINT_LOGGING
+static const char * const SDL_priority_names[] = {
+    NULL,
+    "TRACE",
+    "VERBOSE",
+    "DEBUG",
+    "INFO",
+    "WARN",
+    "ERROR",
+    "CRITICAL"
+};
+SDL_COMPILE_TIME_ASSERT(priority_names, SDL_arraysize(SDL_priority_names) == SDL_LOG_PRIORITY_COUNT);
+
+// This is guarded by SDL_log_function_lock because it's the logging function that calls GetLogPriorityPrefix()
+static char *SDL_priority_prefixes[SDL_LOG_PRIORITY_COUNT] SDL_GUARDED_BY(SDL_log_function_lock);
+
+// If this list changes, update the documentation for SDL_HINT_LOGGING
+static const char * const SDL_category_names[] = {
+    "APP",
+    "ERROR",
+    "ASSERT",
+    "SYSTEM",
+    "AUDIO",
+    "VIDEO",
+    "RENDER",
+    "INPUT",
+    "TEST",
+    "GPU"
+};
+SDL_COMPILE_TIME_ASSERT(category_names, SDL_arraysize(SDL_category_names) == SDL_LOG_CATEGORY_RESERVED2);
+
+#ifdef HAVE_GCC_DIAGNOSTIC_PRAGMA
+#pragma GCC diagnostic pop
+#endif
+
+#ifdef SDL_PLATFORM_ANDROID
+static int SDL_android_priority[] = {
+    ANDROID_LOG_UNKNOWN,
+    ANDROID_LOG_VERBOSE,
+    ANDROID_LOG_VERBOSE,
+    ANDROID_LOG_DEBUG,
+    ANDROID_LOG_INFO,
+    ANDROID_LOG_WARN,
+    ANDROID_LOG_ERROR,
+    ANDROID_LOG_FATAL
+};
+SDL_COMPILE_TIME_ASSERT(android_priority, SDL_arraysize(SDL_android_priority) == SDL_LOG_PRIORITY_COUNT);
+#endif // SDL_PLATFORM_ANDROID
+
+static void SDLCALL SDL_LoggingChanged(void *userdata, const char *name, const char *oldValue, const char *hint)
+{
+    SDL_ResetLogPriorities();
+}
+
+void SDL_InitLog(void)
+{
+    if (!SDL_ShouldInit(&SDL_log_init)) {
+        return;
+    }
+
+    // If these fail we'll continue without them.
+    SDL_log_lock = SDL_CreateMutex();
+    SDL_log_function_lock = SDL_CreateMutex();
+
+    SDL_AddHintCallback(SDL_HINT_LOGGING, SDL_LoggingChanged, NULL);
+
+    SDL_SetInitialized(&SDL_log_init, true);
+}
+
+void SDL_QuitLog(void)
+{
+    if (!SDL_ShouldQuit(&SDL_log_init)) {
+        return;
+    }
+
+    SDL_RemoveHintCallback(SDL_HINT_LOGGING, SDL_LoggingChanged, NULL);
+
+    CleanupLogPriorities();
+    CleanupLogPrefixes();
+
+    if (SDL_log_lock) {
+        SDL_DestroyMutex(SDL_log_lock);
+        SDL_log_lock = NULL;
+    }
+    if (SDL_log_function_lock) {
+        SDL_DestroyMutex(SDL_log_function_lock);
+        SDL_log_function_lock = NULL;
+    }
+
+    SDL_SetInitialized(&SDL_log_init, false);
+}
+
+static void SDL_CheckInitLog(void)
+{
+    int status = SDL_GetAtomicInt(&SDL_log_init.status);
+    if (status == SDL_INIT_STATUS_INITIALIZED ||
+        (status == SDL_INIT_STATUS_INITIALIZING && SDL_log_init.thread == SDL_GetCurrentThreadID())) {
+        return;
+    }
+
+    SDL_InitLog();
+}
+
+static void CleanupLogPriorities(void)
+{
+    while (SDL_loglevels) {
+        SDL_LogLevel *entry = SDL_loglevels;
+        SDL_loglevels = entry->next;
+        SDL_free(entry);
+    }
+}
+
+void SDL_SetLogPriorities(SDL_LogPriority priority)
+{
+    SDL_CheckInitLog();
+
+    SDL_LockMutex(SDL_log_lock);
+    {
+        CleanupLogPriorities();
+
+        SDL_log_default_priority = priority;
+        for (int i = 0; i < SDL_arraysize(SDL_log_priorities); ++i) {
+            SDL_log_priorities[i] = priority;
+        }
+    }
+    SDL_UnlockMutex(SDL_log_lock);
+}
+
+void SDL_SetLogPriority(int category, SDL_LogPriority priority)
+{
+    SDL_LogLevel *entry;
+
+    SDL_CheckInitLog();
+
+    SDL_LockMutex(SDL_log_lock);
+    {
+        if (category >= 0 && category < SDL_arraysize(SDL_log_priorities)) {
+            SDL_log_priorities[category] = priority;
+        } else {
+            for (entry = SDL_loglevels; entry; entry = entry->next) {
+                if (entry->category == category) {
+                    entry->priority = priority;
+                    break;
+                }
+            }
+
+            if (!entry) {
+                entry = (SDL_LogLevel *)SDL_malloc(sizeof(*entry));
+                if (entry) {
+                    entry->category = category;
+                    entry->priority = priority;
+                    entry->next = SDL_loglevels;
+                    SDL_loglevels = entry;
+                }
+            }
+        }
+    }
+    SDL_UnlockMutex(SDL_log_lock);
+}
+
+SDL_LogPriority SDL_GetLogPriority(int category)
+{
+    SDL_LogLevel *entry;
+    SDL_LogPriority priority = SDL_LOG_PRIORITY_INVALID;
+
+    SDL_CheckInitLog();
+
+    // Bypass the lock for known categories
+    // Technically if the priority was set on a different CPU the value might not
+    // be visible on this CPU for a while, but in practice it's fast enough that
+    // this performance improvement is worthwhile.
+    if (category >= 0 && category < SDL_arraysize(SDL_log_priorities)) {
+        return SDL_log_priorities[category];
+    }
+
+    SDL_LockMutex(SDL_log_lock);
+    {
+        if (category >= 0 && category < SDL_arraysize(SDL_log_priorities)) {
+            priority = SDL_log_priorities[category];
+        } else {
+            for (entry = SDL_loglevels; entry; entry = entry->next) {
+                if (entry->category == category) {
+                    priority = entry->priority;
+                    break;
+                }
+            }
+            if (priority == SDL_LOG_PRIORITY_INVALID) {
+                priority = SDL_log_default_priority;
+            }
+        }
+    }
+    SDL_UnlockMutex(SDL_log_lock);
+
+    return priority;
+}
+
+static bool ParseLogCategory(const char *string, size_t length, int *category)
+{
+    int i;
+
+    if (SDL_isdigit(*string)) {
+        *category = SDL_atoi(string);
+        return true;
+    }
+
+    if (*string == '*') {
+        *category = DEFAULT_CATEGORY;
+        return true;
+    }
+
+    for (i = 0; i < SDL_arraysize(SDL_category_names); ++i) {
+        if (SDL_strncasecmp(string, SDL_category_names[i], length) == 0) {
+            *category = i;
+            return true;
+        }
+    }
+    return false;
+}
+
+static bool ParseLogPriority(const char *string, size_t length, SDL_LogPriority *priority)
+{
+    int i;
+
+    if (SDL_isdigit(*string)) {
+        i = SDL_atoi(string);
+        if (i == 0) {
+            // 0 has a special meaning of "disable this category"
+            *priority = SDL_LOG_PRIORITY_COUNT;
+            return true;
+        }
+        if (i > SDL_LOG_PRIORITY_INVALID && i < SDL_LOG_PRIORITY_COUNT) {
+            *priority = (SDL_LogPriority)i;
+            return true;
+        }
+        return false;
+    }
+
+    if (SDL_strncasecmp(string, "quiet", length) == 0) {
+        *priority = SDL_LOG_PRIORITY_COUNT;
+        return true;
+    }
+
+    for (i = SDL_LOG_PRIORITY_INVALID + 1; i < SDL_LOG_PRIORITY_COUNT; ++i) {
+        if (SDL_strncasecmp(string, SDL_priority_names[i], length) == 0) {
+            *priority = (SDL_LogPriority)i;
+            return true;
+        }
+    }
+    return false;
+}
+
+static void ParseLogPriorities(const char *hint)
+{
+    const char *name, *next;
+    int category = DEFAULT_CATEGORY;
+    SDL_LogPriority priority = SDL_LOG_PRIORITY_INVALID;
+
+    if (SDL_strchr(hint, '=') == NULL) {
+        if (ParseLogPriority(hint, SDL_strlen(hint), &priority)) {
+            SDL_SetLogPriorities(priority);
+        }
+        return;
+    }
+
+    for (name = hint; name; name = next) {
+        const char *sep = SDL_strchr(name, '=');
+        if (!sep) {
+            break;
+        }
+        next = SDL_strchr(sep, ',');
+        if (next) {
+            ++next;
+        }
+
+        if (ParseLogCategory(name, (sep - name), &category)) {
+            const char *value = sep + 1;
+            size_t len;
+            if (next) {
+                len = (next - value - 1);
+            } else {
+                len = SDL_strlen(value);
+            }
+            if (ParseLogPriority(value, len, &priority)) {
+                if (category == DEFAULT_CATEGORY) {
+                    for (int i = 0; i < SDL_arraysize(SDL_log_priorities); ++i) {
+                        if (SDL_log_priorities[i] == SDL_LOG_PRIORITY_INVALID) {
+                            SDL_log_priorities[i] = priority;
+                        }
+                    }
+                    SDL_log_default_priority = priority;
+                } else {
+                    SDL_SetLogPriority(category, priority);
+                }
+            }
+        }
+    }
+}
+
+void SDL_ResetLogPriorities(void)
+{
+    SDL_CheckInitLog();
+
+    SDL_LockMutex(SDL_log_lock);
+    {
+        CleanupLogPriorities();
+
+        SDL_log_default_priority = SDL_LOG_PRIORITY_INVALID;
+        for (int i = 0; i < SDL_arraysize(SDL_log_priorities); ++i) {
+            SDL_log_priorities[i] = SDL_LOG_PRIORITY_INVALID;
+        }
+
+        const char *hint = SDL_GetHint(SDL_HINT_LOGGING);
+        if (hint) {
+            ParseLogPriorities(hint);
+        }
+
+        if (SDL_log_default_priority == SDL_LOG_PRIORITY_INVALID) {
+            SDL_log_default_priority = SDL_LOG_PRIORITY_ERROR;
+        }
+        for (int i = 0; i < SDL_arraysize(SDL_log_priorities); ++i) {
+            if (SDL_log_priorities[i] != SDL_LOG_PRIORITY_INVALID) {
+                continue;
+            }
+
+            switch (i) {
+            case SDL_LOG_CATEGORY_APPLICATION:
+                SDL_log_priorities[i] = SDL_LOG_PRIORITY_INFO;
+                break;
+            case SDL_LOG_CATEGORY_ASSERT:
+                SDL_log_priorities[i] = SDL_LOG_PRIORITY_WARN;
+                break;
+            case SDL_LOG_CATEGORY_TEST:
+                SDL_log_priorities[i] = SDL_LOG_PRIORITY_VERBOSE;
+                break;
+            default:
+                SDL_log_priorities[i] = SDL_LOG_PRIORITY_ERROR;
+                break;
+            }
+        }
+    }
+    SDL_UnlockMutex(SDL_log_lock);
+}
+
+static void CleanupLogPrefixes(void)
+{
+    for (int i = 0; i < SDL_arraysize(SDL_priority_prefixes); ++i) {
+        if (SDL_priority_prefixes[i]) {
+            SDL_free(SDL_priority_prefixes[i]);
+            SDL_priority_prefixes[i] = NULL;
+        }
+    }
+}
+
+static const char *GetLogPriorityPrefix(SDL_LogPriority priority)
+{
+    if (priority <= SDL_LOG_PRIORITY_INVALID || priority >= SDL_LOG_PRIORITY_COUNT) {
+        return "";
+    }
+
+    if (SDL_priority_prefixes[priority]) {
+        return SDL_priority_prefixes[priority];
+    }
+
+    switch (priority) {
+    case SDL_LOG_PRIORITY_WARN:
+        return "WARNING: ";
+    case SDL_LOG_PRIORITY_ERROR:
+        return "ERROR: ";
+    case SDL_LOG_PRIORITY_CRITICAL:
+        return "ERROR: ";
+    default:
+        return "";
+    }
+}
+
+bool SDL_SetLogPriorityPrefix(SDL_LogPriority priority, const char *prefix)
+{
+    char *prefix_copy;
+
+    if (priority <= SDL_LOG_PRIORITY_INVALID || priority >= SDL_LOG_PRIORITY_COUNT) {
+        return SDL_InvalidParamError("priority");
+    }
+
+    if (!prefix || !*prefix) {
+        prefix_copy = SDL_strdup("");
+    } else {
+        prefix_copy = SDL_strdup(prefix);
+    }
+    if (!prefix_copy) {
+        return false;
+    }
+
+    SDL_LockMutex(SDL_log_function_lock);
+    {
+        if (SDL_priority_prefixes[priority]) {
+            SDL_free(SDL_priority_prefixes[priority]);
+        }
+        SDL_priority_prefixes[priority] = prefix_copy;
+    }
+    SDL_UnlockMutex(SDL_log_function_lock);
+
+    return true;
+}
+
+void SDL_Log(SDL_PRINTF_FORMAT_STRING const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    SDL_LogMessageV(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO, fmt, ap);
+    va_end(ap);
+}
+
+void SDL_LogTrace(int category, SDL_PRINTF_FORMAT_STRING const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    SDL_LogMessageV(category, SDL_LOG_PRIORITY_TRACE, fmt, ap);
+    va_end(ap);
+}
+
+void SDL_LogVerbose(int category, SDL_PRINTF_FORMAT_STRING const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    SDL_LogMessageV(category, SDL_LOG_PRIORITY_VERBOSE, fmt, ap);
+    va_end(ap);
+}
+
+void SDL_LogDebug(int category, SDL_PRINTF_FORMAT_STRING const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    SDL_LogMessageV(category, SDL_LOG_PRIORITY_DEBUG, fmt, ap);
+    va_end(ap);
+}
+
+void SDL_LogInfo(int category, SDL_PRINTF_FORMAT_STRING const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    SDL_LogMessageV(category, SDL_LOG_PRIORITY_INFO, fmt, ap);
+    va_end(ap);
+}
+
+void SDL_LogWarn(int category, SDL_PRINTF_FORMAT_STRING const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    SDL_LogMessageV(category, SDL_LOG_PRIORITY_WARN, fmt, ap);
+    va_end(ap);
+}
+
+void SDL_LogError(int category, SDL_PRINTF_FORMAT_STRING const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    SDL_LogMessageV(category, SDL_LOG_PRIORITY_ERROR, fmt, ap);
+    va_end(ap);
+}
+
+void SDL_LogCritical(int category, SDL_PRINTF_FORMAT_STRING const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    SDL_LogMessageV(category, SDL_LOG_PRIORITY_CRITICAL, fmt, ap);
+    va_end(ap);
+}
+
+void SDL_LogMessage(int category, SDL_LogPriority priority, SDL_PRINTF_FORMAT_STRING const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    SDL_LogMessageV(category, priority, fmt, ap);
+    va_end(ap);
+}
+
+#ifdef SDL_PLATFORM_ANDROID
+static const char *GetCategoryPrefix(int category)
+{
+    if (category < SDL_LOG_CATEGORY_RESERVED2) {
+        return SDL_category_names[category];
+    }
+    if (category < SDL_LOG_CATEGORY_CUSTOM) {
+        return "RESERVED";
+    }
+    return "CUSTOM";
+}
+#endif // SDL_PLATFORM_ANDROID
+
+void SDL_LogMessageV(int category, SDL_LogPriority priority, SDL_PRINTF_FORMAT_STRING const char *fmt, va_list ap)
+{
+    char *message = NULL;
+    char stack_buf[SDL_MAX_LOG_MESSAGE_STACK];
+    size_t len_plus_term;
+    int len;
+    va_list aq;
+
+    // Nothing to do if we don't have an output function
+    if (!SDL_log_function) {
+        return;
+    }
+
+    // See if we want to do anything with this message
+    if (priority < SDL_GetLogPriority(category)) {
+        return;
+    }
+
+    // Render into stack buffer
+    va_copy(aq, ap);
+    len = SDL_vsnprintf(stack_buf, sizeof(stack_buf), fmt, aq);
+    va_end(aq);
+
+    if (len < 0) {
+        return;
+    }
+
+    // If message truncated, allocate and re-render
+    if (len >= sizeof(stack_buf) && SDL_size_add_check_overflow(len, 1, &len_plus_term)) {
+        // Allocate exactly what we need, including the zero-terminator
+        message = (char *)SDL_malloc(len_plus_term);
+        if (!message) {
+            return;
+        }
+        va_copy(aq, ap);
+        len = SDL_vsnprintf(message, len_plus_term, fmt, aq);
+        va_end(aq);
+    } else {
+        message = stack_buf;
+    }
+
+    // Chop off final endline.
+    if ((len > 0) && (message[len - 1] == '\n')) {
+        message[--len] = '\0';
+        if ((len > 0) && (message[len - 1] == '\r')) { // catch "\r\n", too.
+            message[--len] = '\0';
+        }
+    }
+
+    SDL_LockMutex(SDL_log_function_lock);
+    {
+        SDL_log_function(SDL_log_userdata, category, priority, message);
+    }
+    SDL_UnlockMutex(SDL_log_function_lock);
+
+    // Free only if dynamically allocated
+    if (message != stack_buf) {
+        SDL_free(message);
+    }
+}
+
+#if defined(SDL_PLATFORM_WIN32) && !defined(SDL_PLATFORM_GDK)
+enum {
+    CONSOLE_UNATTACHED = 0,
+    CONSOLE_ATTACHED_CONSOLE = 1,
+    CONSOLE_ATTACHED_FILE = 2,
+    CONSOLE_ATTACHED_ERROR = -1,
+} consoleAttached = CONSOLE_UNATTACHED;
+
+// Handle to stderr output of console.
+static HANDLE stderrHandle = NULL;
+#endif
+
+static void SDLCALL SDL_LogOutput(void *userdata, int category, SDL_LogPriority priority,
+                                  const char *message)
+{
+#if defined(SDL_PLATFORM_WINDOWS)
+    // Way too many allocations here, urgh
+    // Note: One can't call SDL_SetError here, since that function itself logs.
+    {
+        char *output;
+        size_t length;
+        LPTSTR tstr;
+        bool isstack;
+
+#if !defined(SDL_PLATFORM_GDK)
+        BOOL attachResult;
+        DWORD attachError;
+        DWORD consoleMode;
+        DWORD charsWritten;
+
+        // Maybe attach console and get stderr handle
+        if (consoleAttached == CONSOLE_UNATTACHED) {
+            attachResult = AttachConsole(ATTACH_PARENT_PROCESS);
+            if (!attachResult) {
+                attachError = GetLastError();
+                if (attachError == ERROR_INVALID_HANDLE) {
+                    // This is expected when running from Visual Studio
+                    // OutputDebugString(TEXT("Parent process has no console\r\n"));
+                    consoleAttached = CONSOLE_ATTACHED_ERROR;
+                } else if (attachError == ERROR_GEN_FAILURE) {
+                    OutputDebugString(TEXT("Could not attach to console of parent process\r\n"));
+                    consoleAttached = CONSOLE_ATTACHED_ERROR;
+                } else if (attachError == ERROR_ACCESS_DENIED) {
+                    // Already attached
+                    consoleAttached = CONSOLE_ATTACHED_CONSOLE;
+                } else {
+                    OutputDebugString(TEXT("Error attaching console\r\n"));
+                    consoleAttached = CONSOLE_ATTACHED_ERROR;
+                }
+            } else {
+                // Newly attached
+                consoleAttached = CONSOLE_ATTACHED_CONSOLE;
+            }
+
+            if (consoleAttached == CONSOLE_ATTACHED_CONSOLE) {
+                stderrHandle = GetStdHandle(STD_ERROR_HANDLE);
+
+                if (GetConsoleMode(stderrHandle, &consoleMode) == 0) {
+                    // WriteConsole fails if the output is redirected to a file. Must use WriteFile instead.
+                    consoleAttached = CONSOLE_ATTACHED_FILE;
+                }
+            }
+        }
+#endif // !defined(SDL_PLATFORM_GDK)
+        length = SDL_strlen(GetLogPriorityPrefix(priority)) + SDL_strlen(message) + 1 + 1 + 1;
+        output = SDL_small_alloc(char, length, &isstack);
+        if (!output) {
+            return;
+        }
+        (void)SDL_snprintf(output, length, "%s%s\r\n", GetLogPriorityPrefix(priority), message);
+        tstr = WIN_UTF8ToString(output);
+
+        // Output to debugger
+        OutputDebugString(tstr);
+
+#if !defined(SDL_PLATFORM_GDK)
+        // Screen output to stderr, if console was attached.
+        if (consoleAttached == CONSOLE_ATTACHED_CONSOLE) {
+            if (!WriteConsole(stderrHandle, tstr, (DWORD)SDL_tcslen(tstr), &charsWritten, NULL)) {
+                OutputDebugString(TEXT("Error calling WriteConsole\r\n"));
+                if (GetLastError() == ERROR_NOT_ENOUGH_MEMORY) {
+                    OutputDebugString(TEXT("Insufficient heap memory to write message\r\n"));
+                }
+            }
+
+        } else if (consoleAttached == CONSOLE_ATTACHED_FILE) {
+            if (!WriteFile(stderrHandle, output, (DWORD)SDL_strlen(output), &charsWritten, NULL)) {
+                OutputDebugString(TEXT("Error calling WriteFile\r\n"));
+            }
+        }
+#endif // !defined(SDL_PLATFORM_GDK)
+
+        SDL_free(tstr);
+        SDL_small_free(output, isstack);
+    }
+#elif defined(SDL_PLATFORM_ANDROID)
+    {
+        char tag[32];
+
+        SDL_snprintf(tag, SDL_arraysize(tag), "SDL/%s", GetCategoryPrefix(category));
+        __android_log_write(SDL_android_priority[priority], tag, message);
+    }
+#elif defined(SDL_PLATFORM_APPLE) && (defined(SDL_VIDEO_DRIVER_COCOA) || defined(SDL_VIDEO_DRIVER_UIKIT))
+    /* Technically we don't need Cocoa/UIKit, but that's where this function is defined for now.
+     */
+    extern void SDL_NSLog(const char *prefix, const char *text);
+    {
+        SDL_NSLog(GetLogPriorityPrefix(priority), message);
+        return;
+    }
+#elif defined(SDL_PLATFORM_PSP) || defined(SDL_PLATFORM_PS2)
+    {
+        FILE *pFile;
+        pFile = fopen("SDL_Log.txt", "a");
+        if (pFile) {
+            (void)fprintf(pFile, "%s%s\n", GetLogPriorityPrefix(priority), message);
+            (void)fclose(pFile);
+        }
+    }
+#elif defined(SDL_PLATFORM_VITA)
+    {
+        FILE *pFile;
+        pFile = fopen("ux0:/data/SDL_Log.txt", "a");
+        if (pFile) {
+            (void)fprintf(pFile, "%s%s\n", GetLogPriorityPrefix(priority), message);
+            (void)fclose(pFile);
+        }
+    }
+#elif defined(SDL_PLATFORM_3DS)
+    {
+        FILE *pFile;
+        pFile = fopen("sdmc:/3ds/SDL_Log.txt", "a");
+        if (pFile) {
+            (void)fprintf(pFile, "%s%s\n", GetLogPriorityPrefix(priority), message);
+            (void)fclose(pFile);
+        }
+    }
+#endif
+#if defined(HAVE_STDIO_H) && \
+    !(defined(SDL_PLATFORM_APPLE) && (defined(SDL_VIDEO_DRIVER_COCOA) || defined(SDL_VIDEO_DRIVER_UIKIT))) && \
+    !(defined(SDL_PLATFORM_WIN32))
+    (void)fprintf(stderr, "%s%s\n", GetLogPriorityPrefix(priority), message);
+#endif
+}
+
+SDL_LogOutputFunction SDL_GetDefaultLogOutputFunction(void)
+{
+    return SDL_LogOutput;
+}
+
+void SDL_GetLogOutputFunction(SDL_LogOutputFunction *callback, void **userdata)
+{
+    SDL_LockMutex(SDL_log_function_lock);
+    {
+        if (callback) {
+            *callback = SDL_log_function;
+        }
+        if (userdata) {
+            *userdata = SDL_log_userdata;
+        }
+    }
+    SDL_UnlockMutex(SDL_log_function_lock);
+}
+
+void SDL_SetLogOutputFunction(SDL_LogOutputFunction callback, void *userdata)
+{
+    SDL_LockMutex(SDL_log_function_lock);
+    {
+        SDL_log_function = callback;
+        SDL_log_userdata = userdata;
+    }
+    SDL_UnlockMutex(SDL_log_function_lock);
+}