From 1ff483d1f3cce0d5f63e4008ececbf2fdfc7268e Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Fri, 13 Mar 2020 21:28:09 -0700
Subject: [PATCH] Added SDL_GetErrorMsg() to get the error message in a
 thread-safe way

---
 include/SDL_error.h               | 38 ++++++++++++++++++++++++++++++-
 src/SDL_error.c                   |  4 +---
 src/dynapi/SDL_dynapi_overrides.h |  1 +
 src/dynapi/SDL_dynapi_procs.h     |  1 +
 4 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/include/SDL_error.h b/include/SDL_error.h
index aae37c0e46058..962d62f6eb472 100644
--- a/include/SDL_error.h
+++ b/include/SDL_error.h
@@ -37,9 +37,45 @@ extern "C" {
 #endif
 
 /* Public functions */
-/* SDL_SetError() unconditionally returns -1. */
+
+
+/**
+ *  \brief Set the error message for the current thread
+ *
+ *  \return -1, there is no error handling for this function
+ */
 extern DECLSPEC int SDLCALL SDL_SetError(SDL_PRINTF_FORMAT_STRING const char *fmt, ...) SDL_PRINTF_VARARG_FUNC(1);
+
+/**
+ *  \brief Get the last error message that was set
+ *
+ * SDL API functions may set error messages and then succeed, so you should
+ * only use the error value if a function fails.
+ * 
+ * This returns a pointer to a static buffer for convenience and should not
+ * be called by multiple threads simultaneously.
+ *
+ *  \return a pointer to the last error message that was set
+ */
 extern DECLSPEC const char *SDLCALL SDL_GetError(void);
+
+/**
+ *  \brief Get the last error message that was set for the current thread
+ *
+ * SDL API functions may set error messages and then succeed, so you should
+ * only use the error value if a function fails.
+ * 
+ *  \param errstr A buffer to fill with the last error message that was set
+ *                for the current thread
+ *  \param maxlen The size of the buffer pointed to by the errstr parameter
+ *
+ *  \return errstr
+ */
+extern DECLSPEC char * SDLCALL SDL_GetErrorMsg(char *errstr, int maxlen);
+
+/**
+ *  \brief Clear the error message for the current thread
+ */
 extern DECLSPEC void SDLCALL SDL_ClearError(void);
 
 /**
diff --git a/src/SDL_error.c b/src/SDL_error.c
index 36f8003348fba..bf17087c1d122 100644
--- a/src/SDL_error.c
+++ b/src/SDL_error.c
@@ -39,8 +39,6 @@ SDL_LookupString(const char *key)
 
 /* Public functions */
 
-static char *SDL_GetErrorMsg(char *errstr, int maxlen);
-
 int
 SDL_SetError(SDL_PRINTF_FORMAT_STRING const char *fmt, ...)
 {
@@ -192,7 +190,7 @@ main(int argc, char *argv[])
 /* This function has a bit more overhead than most error functions
    so that it supports internationalization and thread-safe errors.
 */
-static char *
+char *
 SDL_GetErrorMsg(char *errstr, int maxlen)
 {
     SDL_error *error;
diff --git a/src/dynapi/SDL_dynapi_overrides.h b/src/dynapi/SDL_dynapi_overrides.h
index d6476a2eec255..e2a44b0be7649 100644
--- a/src/dynapi/SDL_dynapi_overrides.h
+++ b/src/dynapi/SDL_dynapi_overrides.h
@@ -756,3 +756,4 @@
 #define SDL_JoystickSetVirtualBall SDL_JoystickSetVirtualBall_REAL
 #define SDL_JoystickSetVirtualButton SDL_JoystickSetVirtualButton_REAL
 #define SDL_JoystickSetVirtualHat SDL_JoystickSetVirtualHat_REAL
+#define SDL_GetErrorMsg SDL_GetErrorMsg_REAL
diff --git a/src/dynapi/SDL_dynapi_procs.h b/src/dynapi/SDL_dynapi_procs.h
index 2d8a291d64384..160ac76ef5910 100644
--- a/src/dynapi/SDL_dynapi_procs.h
+++ b/src/dynapi/SDL_dynapi_procs.h
@@ -816,3 +816,4 @@ SDL_DYNAPI_PROC(int,SDL_JoystickSetVirtualAxis,(SDL_Joystick *a, int b, Sint16 c
 SDL_DYNAPI_PROC(int,SDL_JoystickSetVirtualBall,(SDL_Joystick *a, int b, Sint16 c, Sint16 d),(a,b,c,d),return)
 SDL_DYNAPI_PROC(int,SDL_JoystickSetVirtualButton,(SDL_Joystick *a, int b, Uint8 c),(a,b,c),return)
 SDL_DYNAPI_PROC(int,SDL_JoystickSetVirtualHat,(SDL_Joystick *a, int b, Uint8 c),(a,b,c),return)
+SDL_DYNAPI_PROC(char*,SDL_GetErrorMsg,(char *a, int b),(a,b),return)