SQLITE源码剖析(13)

 声明：本SQLite源码剖析系列为刘兴(http://deepfuture.iteye.com/)原创，未经笔者授权，任何人和机构不能转载

//第一个参数的每个回调请求被转到sqlite3_exec() 的第4个参数，

//如果指向sqlite3_exec()的回调指针是NULL，则没有回调被调用，

//且结果行被忽略。

**^The 4th argument to

** to sqlite3_exec() is relayed through to the 1st argument of each

** callback invocation.  ^If the callback pointer to sqlite3_exec()

** is NULL, then no callback is ever invoked and result rows are

** ignored.

**当执行SQL语句时，如果错误发生在sqlite3_exec()中,则当前语句

**的执行停止，且子语句被跳过。如果sqlite3_exec()的第5个参

**数非NULL，则error信息被写入从sqlite3_malloc()分配的内存。为防

**内存泄露，应用程序必须调用sqlite3_free()释放从sqlite3_exec()的

**第5个参数返回的错误信息字符串，当这些错误信息字符串不再需要时。

**如果sqlite3_exec()的第5个参数为非NULL且没有错误发生，

**sqlite3_exec()返回前将设置其为NULL

** ^If an error occurs while evaluating the SQL statements passed into

** sqlite3_exec(), then execution of the current statement stops and

** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()

** is not NULL then any error message is written into memory obtained

** from [sqlite3_malloc()] and passed back through the 5th parameter.

** To avoid memory leaks, the application should invoke [sqlite3_free()]

** on error message strings returned through the 5th parameter of

** of sqlite3_exec() after the error message string is no longer needed.

** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors

** occur, then sqlite3_exec() sets the pointer in its 5th parameter to

** NULL before returning.

**如果sqlite3_exec()回调返回非0,则sqlite3_exec()通常

**返回SQLITE_ABORT，不运行任何后来的SQL语句

** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()

** routine returns SQLITE_ABORT without invoking the callback again and

** without running any subsequent SQL statements.