Clarifications to the sqlite3_auto_extension() documentation.

FossilOrigin-Name: ca96e0df29cad4a9c7395a0acf623d8a19cb4725

1 files changed, 32 insertions, 19 deletions

diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 7944a0d60..d54f9743b 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -4358,34 +4358,47 @@ int sqlite3_load_extension(
 int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
 
 /*
-** CAPI3REF: Automatically Load An Extensions
+** CAPI3REF: Automatically Load Statically Linked Extensions
 **
-** ^This API can be invoked at program startup in order to register
-** one or more statically linked extensions that will be available
-** to all new [database connections].
+** ^This interface causes the xEntryPoint() function to be invoked for
+** each new [database connection] that is created.  The idea here is that
+** xEntryPoint() is the entry point for a statically linked SQLite extension
+** that is to be automatically loaded into all new database connections.
 **
-** ^(This routine stores a pointer to the extension entry point
-** in an array that is obtained from [sqlite3_malloc()].  That memory
-** is deallocated by [sqlite3_reset_auto_extension()].)^
+** ^(Even though the function prototype shows that xEntryPoint() takes
+** no arguments and returns void, SQLite invokes xEntryPoint() with three
+** arguments and expects and integer result as if the signature of the
+** entry point where as follows:
 **
-** ^This function registers an extension entry point that is
-** automatically invoked whenever a new [database connection]
-** is opened using [sqlite3_open()], [sqlite3_open16()],
-** or [sqlite3_open_v2()].
-** ^Duplicate extensions are detected so calling this routine
-** multiple times with the same extension is harmless.
-** ^Automatic extensions apply across all threads.
+** <blockquote><pre>
+** &nbsp;  int xEntryPoint(
+** &nbsp;    sqlite3 *db,
+** &nbsp;    const char **pzErrMsg,
+** &nbsp;    const struct sqlite3_api_routines *pThunk
+** &nbsp;  );
+** </pre></blockquote>)^
+**
+** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
+** point to an appropriate error message (obtained from [sqlite3_mprintf()])
+** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
+** is NULL before calling the xEntryPoint().  ^SQLite will invoke
+** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
+** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
+** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
+**
+** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
+** on the list of automatic extensions is a harmless no-op. ^No entry point
+** will be called more than once for each database connection that is opened.
+**
+** See also: [sqlite3_reset_auto_extension()].
 */
 int sqlite3_auto_extension(void (*xEntryPoint)(void));
 
 /*
 ** CAPI3REF: Reset Automatic Extension Loading
 **
-** ^(This function disables all previously registered automatic
-** extensions. It undoes the effect of all prior
-** [sqlite3_auto_extension()] calls.)^
-**
-** ^This function disables automatic extensions in all threads.
+** ^This interface disables all automatic extensions previously
+** registered using [sqlite3_auto_extension()].
 */
 void sqlite3_reset_auto_extension(void);