sqlite3_exec回调是同步的还是异步的?

Is sqlite3_exec callback synchronous or asynchronous?

带有回调参数的 Sqlite3 函数 sqlite3_exec() 是同步运行还是异步运行?

调用示例:

int retStatus = sqlite3_exec(pDB, "SELECT * FROM SomeTable WHERE Something='Hi'", callback, &object, &error);

...Next line(s) of code...

同步。在代码继续之前为找到的每一行调用回调:

static int _getName(void* pNames, int columns, char** data, char** columnNames)
{
    if (columns < 2)
    {
        assert(false && "Function called on wrong table!");
        // Signify failure
        return 1;
    }
    std::vector<std::string>* vNames = static_cast< std::vector<std::string>* >(pNames);
    vNames->push_back(data[1]);
    // Success:
    return 0;
}

{
    std::vector<std::string> names;
    // assume pDB is a valid, opened sqlite3* db
    char* error = 0;
    if (sqlite3_exec(pDB, "SELECT * FROM TableNames", _getName, static_cast<void*>(&names), &error) != SQLITE_OK)
    {
        // log and free error:
    }

    assert(names.size() && "No entries were found in the table");
}

_getName 将在 table TableNames 中找到的每个条目上调用。如果未找到任何条目,则不会调用该函数,也不会出现错误。如果您 table 调用了具有 10 个条目的 TableNames,则 names.size() == 10_getName 如果 returns 非零

将不再被调用