DECLARE LONG  setsockopt IN "Ws2_32" long s ,long level,long optname ,long optval ,long optlen  &&"wsock32.dll"
DECLARE LONG  getsockopt IN "Ws2_32" long s ,long level,long optname ,long @optval ,long optlen&&"wsock32.dll"
#define  SOL_SOCKET  65535
#define SO_REUSEADDR 0x0004

setsockopt(Thisform.tcpClient.OBJECT.SocketHandle, SOL_SOCKET, SO_REUSEADDR, 1, 1)

C语言使用如下
*!*        int on = 1;
*!*        setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));



为了解决Address in use C:\Windows\SysWOW64\mswinsck.ocx

[此贴子已经被作者于2023-8-28 09:32编辑过]

原型
int setsockopt(
  [in] SOCKET     s,
  [in] int        level,
  [in] int        optname,
  [in] const char *optval,
  [in] int        optlen
);
注意optval是char*类型

char*类型 在VFP中怎么写？

//C++代码 dll.h
#ifndef LIB_H
#define LIB_H
extern "C" _declspec(dllexport) char* enciphering(char *ch,int &key);
extern "C" _declspec(dllexport) char* deciphering(char *ch,int &key);
#endif

 
//C++代码 Sercret.cpp
#include <iostream>
#include "dll.h"
using namespace std;
char* enciphering(char *ch,int &key)
{
    char *str=new char[100];
    int i=0,x;
    bool decide=true;
    while(ch[i])
    {
        if(ch[i]>='a'&&ch[i]<='z')
        {
            x = ch[i] + i + key + 1;
            while(decide)
            {
                if(x>'z')
                    x-=26;
                else
                    decide=false;
            }
            decide=true;
            str[i]=x;
        }
        else
            str[i]=ch[i];
        i++;
    }
    return str;
}
char* deciphering(char *ch,int &key)
{
    char *str=new char[100];
    int i=0,x;
    bool decide=true;
    while(ch[i])
    {
        if(ch[i]>='a'&&ch[i]<='z')
        {
            x=ch[i]-i-1-key;
            while(decide)
            {
                if(x<'a')
                    x+=26;
                else
                    decide=false;
            }
            decide=true;
            str[i]=x;
        }
        else
str[i]=ch[i];
        i++;
    }
    return str;
}

 

//编译后dll被VFP调用
Declare String enciphering in s_sercret.dll String @, Integer @
Declare String deciphering in s_sercret.dll String @, Integer @

通常char*类型可看作vfp的字符串类型，如果涉及到unicode可能要在尾部添加0h00（chr(0)）。
函数声明时通常是string@，如果只作为输入参数（in）可不用描写“@”。
提供的示例：
C语言使用如下
*!*        int on = 1;
*!*        setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
代码不清楚出处，有些编译器对这种语句描述可能会有警告提示（因强制类型转换不太严谨）。
setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, (char*)&on, sizeof(on));
vfp可用BINTOC(on,"4rs")来表达

DECLARE LONG  setsockopt IN "Ws2_32" long s ,long level,long optname ,string optval ,long optlen  &&"wsock32.dll"
DECLARE LONG  getsockopt IN "Ws2_32" long s ,long level,long optname ,string @optval ,long optlen


optval= REPLICATE(0h00,4)
setsockopt( this.obJECT.SocketHandle, SOL_SOCKET, SO_REUSEADDR, bintoc(1,"4rs")  , 1)
?getsockopt(this.obJECT.SocketHandle, SOL_SOCKET, SO_REUSEADDR,@optval, 4),optval


这样写？

optlen都是4

学习

是不是UDP协议无效果？
optval= REPLICATE(0h00,4)
setsockopt( this.obJECT.SocketHandle, SOL_SOCKET, SO_REUSEADDR, bintoc(1,"4rs")  , 4)
?getsockopt(this.obJECT.SocketHandle, SOL_SOCKET, SO_REUSEADDR,@optval, 4),optval

返回-1

跟着用 WSAGetLastError() 看看