我正在尝试学习C++,在做一个连接到MySQL数据库的测试时,我做了一些噩梦。
我曾经遇到过MySQL连接器连接不正确的问题,然后又遇到了与relocation truncated to fitr_x86_64_32 against symbol
相关的问题。
我想我已经修复了这个问题,添加了一个编译器标志,现在应用程序成功地构建和链接了。
当我运行这个应用程序时,它会一直调用get_driver_instance,但随后就退出了。没有抛出异常,没有错误,什么都没有,只是退出代码0。
下面是我的DBManager类
#include "DBConnectionManager.h"
using namespace std;
DBConnectionManager::DBConnectionManager() {
cout << "Starting DBConnectionManager - Updated" << endl;
try {
cout << "Getting driver instance" << endl;
driver = get_driver_instance();
cout << "Got driver instance" << endl;
conn = driver->connect("tcp://127.0.0.1:3306", "root", "password");
conn->setSchema("bugs");
cout << "Connected to database" << endl;
}
catch (SQLException ex) {
cout << "Error connecting to DB: " << ex.what() << endl;
}
catch (...) {
cout << "Something has gone wrong" << endl;
}
}
下面是头文件
#ifndef MYSQLTEST_DBCONNECTIONMANAGER_H
#define MYSQLTEST_DBCONNECTIONMANAGER_H
#include <driver.h>
#include <exception.h>
#include <resultset.h>
#include <statement.h>
using namespace sql;
class DBConnectionManager
{
private:
sql::Driver *driver;
sql::Connection *conn;
sql::Statement *statement;
sql::ResultSet *res;
public:
DBConnectionManager();
void performSql();
};
#endif //MYSQLTEST_DBCONNECTIONMANAGER_H
下面是我的主要方法
#include "DBConnectionManager.h"
int main() {
DBConnectionManager dbConnectionManager;
dbConnectionManager.performSql();
return 0;
}
下面是我的CMakeLists.txt文件
cmake_minimum_required(VERSION 3.6)
project(MySQLTest)
include_directories("C:\\Program Files\\MySQL\\MySQL Connector C++ 1.1.7\\include\\cppconn" "C:\\Program Files\\MySQL\\MySQL Connector C++ 1.1.7\\lib\\opt")
SET(GCC_COVERAGE_LINK_FLAGS "-m64 -Wl,--image-base -Wl,0x10000000 -lpthread -pthread")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -m64 -Wl,--image-base -Wl,0x10000000 -lpthread -pthread ")
set(SOURCE_FILES main.cpp DBConnectionManager.cpp)
add_executable(MySQLTest ${SOURCE_FILES})
add_library(mysqlcppconn.lib)
set_target_properties(MySQLTest PROPERTIES LINKER_LANGUAGE CXX)
set_target_properties(mysqlcppconn.lib PROPERTIES LINKER_LANGUAGE CXX)
target_link_libraries(MySQLTest "C:\\Program Files\\MySQL\\MySQL Connector C++ 1.1.7\\lib\\opt\\mysqlcppconn.lib")
当我创建DBConnectionManager
类的实例时,它成功地调用了查询并输出了Starting DBConnectionManager - Updated
,然后输出了Getting Driver Instance
,但是随后它退出并返回了Process finished with exit code 0
,没有任何线索表明出了什么问题。
更新
我终于有所收获了。我发现Cygwin中有一些MySQL客户端库,所以我下载了它们,并在cmake文件中引用了它们。
我的cmake文件现在看起来像这样:
cmake_minimum_required(VERSION 3.6)
project(MySQLTest)
SET(CPPCONN_PUBLIC_FUNC=)
SET(GCC_COVERAGE_LINK_FLAGS "-g -m64 -DCPPCONN_PUBLIC_FUNC= -Dmysqlcppconn_EXPORTS -lpthread -pthread -Wl,--image-base -Wl,0x10000000 -lz")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DCPPCONN_PUBLIC_FUNC= -Dmysqlcppconn_EXPORTS -std=c++11 -g -m64 -Wl,--image-base -Wl,0x10000000 -lpthread -pthread -lz")
include_directories("C:/mysql_connector/include")
include_directories("C:/boost_1_61_0")
set(BOOST_INCLUDE_DIR C:/boost_1_61_0)
set(BOOST_LIBRARY_DIR C:/boost_1_61_0/libs)
set(SOURCE_FILES main.cpp DBConnectionManager.cpp)
add_executable(MySQLTest ${SOURCE_FILES})
find_package(Boost COMPONENTS REQUIRED)
link_directories(C:/mysql_connector/lib)
target_link_libraries(MySQLTest "C:/mysql_connector/lib/mysqlcppconn.dll" "C:/Program Files/MySQL/MySQL Server 5.7/lib/libmysql.dll" "C:/mysql_connector/lib/libmysqlclient.dll.a" "C:/mysql_connector/lib/libmysqlclient_r.dll.a" ${Boost_LIBRARY_DIR})
注意我是如何链接libmysqlclient.dll.a和libmysqlclient_r.dll.a的,这是我从Cygwin得到的。
现在,当我运行应用程序时,它成功地获取了驱动程序实例,并输出到控制台
Starting DBConnectionManaged - Updated
Getting driver instance
Got driver instance
但是当我尝试使用driver->connect进行连接时,我得到了以下错误
0 [main] MySQLTest 2976 C:\Users\Chris\.CLion2016.2\system\cmake\generated\MySQLTest-8702ae13\8702ae13\Debug\MySQLTest.exe: *** fatal error - Internal error: TP_NUM_C_BUFS too small: 50
当我将它放入调试器时,它在驱动程序上失败了->连接到
gdb: unknown target exception 0xe06d7363 at 0x7fff11347788
Program received signal ?, Unknown signal.
0x00007fff11347788 in RaiseException () from /cygdrive/c/WINDOWS/System32/KERNELBASE.dll
更新2
我读到的所有东西都表明mysql连接器二进制文件应该可以正常工作,所以我又重新开始了。下面是我的cmake文件的内容
cmake_minimum_required(VERSION 3.6)
project(MySQLTest)
#add_compile_options("-v")
SET(GCC_COVERAGE_LINK_FLAGS )
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
set(BOOST_INCLUDE_DIR C:/boost_1_61_0)
set(BOOST_LIBRARY_DIR C:/boost_1_61_0/libs)
include_directories("C:/Program\ Files/MySQL/MySQL\ Connector\ C++\ 1.1.7/include" "C:/Program\ Files/MySQL/MySQL\ Connector\ C++\ 1.1.7/include/cppconn" ${BOOST_INCLUDE_DIR})
set(SOURCE_FILES main.cpp DBConnectionManager.cpp)
add_executable(MySQLTest ${SOURCE_FILES})
find_package(Boost COMPONENTS REQUIRED)
link_directories(C:/Program\ Files/MySQL/MySQL\ Connector\ C++\ 1.1.7/lib/opt)
target_link_libraries(MySQLTest C:/Program\ Files/MySQL/MySQL\ Connector\ C++\ 1.1.7/lib/opt/mysqlcppconn.lib ${Boost_LIBRARY_DIR})
现在,当我编译时,我得到了原始的错误
C:/Program Files/MySQL/MySQL Connector C++ 1.1.7/lib/opt/mysqlcppconn.lib(mysqlcppconn.dll.b):(.text+0x2): relocation truncated to fit: R_X86_64_32 against symbol `__imp_get_driver_instance' defined in .idata$5 section in C:/Program Files/MySQL/MySQL Connector C++ 1.1.7/lib/opt/mysqlcppconn.lib(mysqlcppconn.dll.b)
这听起来像是我的应用程序编译为32位而不是64位。作为测试,我运行了以下代码:
cout << "Int size is: " << sizeof(int) << endl;
上面的代码打印4(如果它被编译为64位,它不应该是8)。
如果我的想法是正确的,为什么不将其编译为64位,我已经尝试设置编译器标志-m64
,但没有什么不同。我也安装了CLion正在使用的Cygwinx64。
https://stackoverflow.com/questions/39730670
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