C++ 下编译pthread的问题
开始我是这样写的
void* startListen(void *)
{
........
}
/////
pthread_create(&socketListen,NULL, startListen, NULL);
这个时候是可以正常编译的，也能执行。
可是我想把它写到一个类中封装起来，改为如下：
void* AcdSocket::startListen(void *)
{........}
pthread_create(&socketListen,NULL, (void *)startListen, NULL);
报错：
错误： invalid use of member (did you forget the ‘&’ ?)
//////////
再改为：
void AcdSocket::startListen(void *)
{........}
pthread_create(&socketListen,NULL, (void *)&startListen, NULL);
报错：
错误： 从类型 ‘void*’ 到类型 ‘void* (*)(void*)’ 的转换无效
编译语句：
g++ main.cpp acdsocket.cpp -lpthread -o acd
g++版本
g++ (GCC) 4.0.3 (Ubuntu 4.0.3-1ubuntu5)
系统：
ubuntu 6.06
[解决办法]
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#ifdef WIN32
#include <windows.h>
typedef unsigned long APIRETURN;
typedef unsigned long (__stdcall * funcptr)(void *);
#else
#include <pthread.h>
#include <unistd.h>
typedef void * APIRETURN;
#endif
#include <iostream>
#include <errmsg.h>
#include <time.h>
using namespace std;
/*****************************************************************/
///name : main
//function : 主测试函数
//access : private
//para :
// 1. : int argc
// : 系统参数个数
// 2. : char * argv[]
// : 参数数值
//return : 返回给 startup 函数的退出参数
//author : hzh
//date : 2006-06-24
/*****************************************************************/
#include "../db/connectpool.h "
using namespace std;
#include <mysql.h>
APIRETURN insert(void * para)
{
for(;;)
{
for(int i = 0;i < 200;++i)
{
CMysqlClient client;
CMysqlStore store;
if(!store.SetTransAction(client.GetConnect()))
{
//std::cout < < "db connect pool busy on insert " < <endl;
break;
}
std::string s_sql = " ";
s_sql = "insert into processingtransactioninterface ";
s_sql += "(acttype,resourceid,actresult,memo) values( ";
s_sql += "1,1,1, '发的沙 ') ";
if(!store.Exec(s_sql))
{
//执行SQL语句出错
store.RollBack();
std::cout < < "execute insert syntax fail, " < <store.What().c_str() < <endl;
}
else
{
store.Commit();
}
}
#ifdef WIN32
Sleep(DWORD(1000 * 0.01));
#else
sleep(1);
#endif
}
return 0;
}
APIRETURN update(void * para)
{
for(;;)
{
for(;;)
{
CMysqlClient client;
CMysqlStore store;
if(!store.SetTransAction(client.GetConnect()))
{
//std::cout < < "db connect pool busy on update " < <endl;
break;
}
std::string s_sql = " ";
s_sql = "update processingtransactioninterface ";
s_sql += " set acttype=2,memo= 'aaa杀 ',actresult=3 ";
s_sql += " where acttype = 1 ";
if(!store.Exec(s_sql))
{
//执行SQL语句出错
store.RollBack();
std::cout < < "execute update syntax fail, " < <store.What().c_str() < <endl;
}
else
{
store.Commit();
}
break;
}
#ifdef WIN32
Sleep(DWORD(1000 * 0.01));
#else
sleep(1);
#endif
}
return 0;
}
APIRETURN show(void * para)
{
for(;;)
{
for(;;)
{
CMysqlClient client;
CMysqlStore store;
if(!store.SetTransAction(client.GetConnect()))
{
//std::cout < < "db connect pool busy on show " < <endl;
break;
}
/*
这可能发生，例如，如果你正在使用mysql_use_result()
并且在你已经调用了mysql_free_result()之前试图
执行新查询。如果你在mysql_use_result()或
mysql_store_result()之间试图执行返回数
据的2个查询，它也可能发生。*/
std::string s_sql = "select * from processingtransactioninterface ";
if(!store.Query(s_sql))
{
//删除表失败
std::cout < < "query table fail, " < <store.What().c_str() < <endl;
}
else
{
for(unsigned long i = 0;i <store.RowCount();++i)
{
std::cout < < "result: " < <store.GetItemLong(i, "actresult ")
< < "\tmemo: " < <store.GetItemString(i, "memo ").c_str()
< < "\tactid: " < <store.GetItemLong(i,0) < <endl;
}
s_sql = "delete from processingtransactioninterface ";
if(!store.Exec(s_sql))
{
//删除表失败
store.RollBack();
std::cout < < "delete table fail, " < <store.What().c_str() < <endl;
}
else
{
store.Commit();
}
}
break;
}
#ifdef WIN32
Sleep(DWORD(1000 * 0.1));
#else
sleep(10);
#endif
}
return 0;
}
int main( int argc, char * argv[] )
{
for(int i = 0;i < 3;++i)
{
std::string host = "127.0.0.1 ";
std::string user = "root ";
std::string password = "mysql5 ";
std::string dbname = "test ";
unsigned int port = MYSQL_PORT;
CConnect * conn = new CMysqlConnect();
conn-> Connect(host,user,password,dbname,port);
CConnPool::Instance().Add(conn);
}
CMysqlClient client;
CMysqlStore store;
store.SetTransAction(client.GetConnect());
//先删除数据表
std::string s_sql = "drop table processingtransactioninterface ";
if(!store.Exec(s_sql))
{
//删除表失败
std::cout < < "drop table fail " < <endl < <store.What().c_str() < <endl;
}
else
{
std::cout < < "drop table success " < <endl;
}
//创建数据表,字段 actid 设置了自增列属性
s_sql = "create table processingtransactioninterface( ";
s_sql += "actid integer not null AUTO_INCREMENT, ";
s_sql += "acttype integer not null,resourceid integer not null, ";
s_sql += " subresoureid integer, actdate varchar(19), actresult integer, ";
s_sql += " memo varchar(50) null,primary key(actid)) ";
if(!store.Exec(s_sql))
{
//创建表失败
std::cout < < "create table fail " < <endl;
return -1;
}
else
{
std::cout < < "create table success " < <endl;
std::cout < <s_sql.c_str() < <endl;
}
#ifdef WIN32
unsigned long p1 = 0;
::CreateThread(0,0,(funcptr)show,0,0,&p1);
#else
pthread_t p1 = 0;
pthread_create(&p1,0,show,0);
#endif
#ifdef WIN32
unsigned long p2 = 0;
::CreateThread(0,0,(funcptr)update,0,0,&p1);
#else
pthread_t p2 = 0;
pthread_create(&p2,0,update,0);
#endif
#ifdef WIN32
unsigned long p3 = 0;
::CreateThread(0,0,(funcptr)insert,0,0,&p1);
#else
pthread_t p3 = 0;
pthread_create(&p1,0,insert,0);
#endif
#ifdef WIN32
system( "pause ");
#else
pause();
#endif
return 1;
}
[解决办法]
不能够将类成员变量函数作为普通函数指针使用。
可以再写一个函数：
AcdSocket socket;
void* startListen(void *s)
{
return socket.startListen(s);
}
就可以了
[解决办法]
很简单的原因
所有的非静态的成员函数的第一个参数都是一个隐式的this指针，因此
void AcdSocket::startListen(void *)等价于
static void AcdSocket::startListen(AcdSocket* this,void *)
这个函数声明当然和pthread所要求的函数类型不同，自然pthread_create不会接受
所以你要做的就是写一个static函数，static函数不会有隐式的this指针
