将自定义sqlite函数添加到Qt应用程序

我正在尝试将自定义sqlite3 regexp函数添加到我的Qt应用程序中(按照此答案的建议).但是一旦我调用该sqlite3_create_function函数,我就会收到消息.The program has unexpectedly finished.当我调试时,它会终止分段错误sqlite3_mutex_enter.下面有一个MWE,对绝对文件路径道歉.

regexp我的代码中的实现来自这个站点 ; 它也失败了这里的msign功能.各种检查直接来自Qt文档.driver()->handle()

顺便说一下,我曾经select sqlite_version();确定Qt 5.5使用的是sqlite版本3.8.8.2.我通过查看Qt GitHub存储库中的旧提交找到了该版本.

MWE.pro

QT       += core gui
TARGET = MWE
TEMPLATE = app
QT += sql
SOURCES += main.cpp \
    D:\Qt\Qt5.5.0\5.5\Src\3rdparty\sqlite\sqlite3.c

HEADERS  += D:\Qt\Qt5.5.0\5.5\Src\3rdparty\sqlite\sqlite3.h

main.cpp中

#include 

#include "D:/Qt/Qt5.5.0/5.5/Src/3rdparty/sqlite/sqlite3.h"

void qtregexp(sqlite3_context* ctx, int argc, sqlite3_value** argv)
{
    QRegExp regex;
    QString str1((const char*)sqlite3_value_text(argv[0]));
    QString str2((const char*)sqlite3_value_text(argv[1]));

    regex.setPattern(str1);
    regex.setCaseSensitivity(Qt::CaseInsensitive);

    bool b = str2.contains(regex);

    if (b)
    {
        sqlite3_result_int(ctx, 1);
    }
    else
    {
        sqlite3_result_int(ctx, 0);
    }
}

int main(int argc, char *argv[])
{
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName("my.db");
    db.open();

    QVariant v = db.driver()->handle();
    if (v.isValid() && qstrcmp(v.typeName(), "sqlite3*")==0) {
        sqlite3 *db_handle = *static_cast(v.data());
        if (db_handle != 0) { // check that it is not NULL
            // This shows that the database handle is generally valid:
            qDebug() << sqlite3_db_filename(db_handle, "main");
            sqlite3_create_function(db_handle, "regexp", 2, SQLITE_UTF8 | SQLITE_DETERMINISTIC, NULL, &qtregexp, NULL, NULL);
            qDebug() << "This won't be reached."

            QSqlQuery query;
            query.prepare("select regexp('p$','tap');");
            query.exec();
            query.next();
            qDebug() << query.value(0).toString();
        }
    }
    db.close();
}

adam.baker.. 6

根据这篇论坛帖子sqlite3_initialize(),你需要在从Qt获得数据库句柄后调用.

    ...
    sqlite3 *db_handle = *static_cast(v.data());
    if (db_handle != 0) { // check that it is not NULL
        sqlite3_initialize();
    ...

这解决了这个问题.

根据这篇论坛帖子sqlite3_initialize(),你需要在从Qt获得数据库句柄后调用.

    ...
    sqlite3 *db_handle = *static_cast(v.data());
    if (db_handle != 0) { // check that it is not NULL
        sqlite3_initialize();
    ...

这解决了这个问题.