描述

 

注册一个可用于跟踪执行SQL语句的回调函数。

 

C / C ++语法

 

 

PB语法

 

 

参数

 

hDbc

 

[in]连接句柄。

 

pTraceCallback

 

[in]指向回调函数的指针。

 

pData

 

[in]一个可选值，它被转发到每个回调调用的第一个参数。

 

返回值

 

先前注册的跟踪回调的pData参数。

 

备注

 

sqlite3_trace注册的回调函数在不同的时候被sqlite3_step运行的SQL语句调用。当语句首先开始执行时，将使用SQL语句文本的UTF-8呈现来调用sqlite3_trace回调。每个触发的子程序都会输入sqlite3_trace回调。触发器的回调包含标识触发器的UTF-8 SQL注释。

 

C ++实现代码

 

#ifndef SQLITE_OMIT_TRACE

/*

** Register a trace function.  The pArg from the previously registered trace

** is returned.

**

** A NULL trace function means that no tracing is executeds.  A non-NULL

** trace is a pointer to a function that is invoked at the start of each

** SQL statement.

*/

SQLITE_API void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){

void *pOld;

sqlite3_mutex_enter(db->mutex);

pOld = db->pTraceArg;

db->xTrace = xTrace;

db->pTraceArg = pArg;

sqlite3_mutex_leave(db->mutex);

return pOld;

}

/*

** Register a profile function.  The pArg from the previously registered

** profile function is returned.

**

** A NULL profile function means that no profiling is executes.  A non-NULL

** profile is a pointer to a function that is invoked at the conclusion of

** each SQL statement that is run.

*/

SQLITE_API void *sqlite3_profile(

sqlite3 *db,

void (*xProfile)(void*,const char*,sqlite_uint64),

void *pArg

){

void *pOld;

sqlite3_mutex_enter(db->mutex);

pOld = db->pProfileArg;

db->xProfile = xProfile;

db->pProfileArg = pArg;

sqlite3_mutex_leave(db->mutex);

return pOld;

}

#endif /* SQLITE_OMIT_TRACE */