found this code on the net, wanted to test winsock, theres an error though, what is 'tolower?

[devonrevenge]

So i want to learn socket programing, first i wanted to make sure i have winsock & winsock2 working before i build anything, i certainly dont want to go round messing with .libs though it drives me mad

i found this code and only one thing is wrong with it, i wondered if you could tell me how to make it work on my editor, because if it works...i can go ahead

the error is on line 46 the hell is tolower??

#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define DEFAULT_PORT 2007
// default TCP socket type
#define DEFAULT_PROTO SOCK_STREAM

void Usage(char *progname)
{
    fprintf(stderr,"Usage: %s -p [protocol] -e [port_num] -i [ip_address]\n", progname);
    fprintf(stderr,"Where:\n\t- protocol is one of TCP or UDP\n");
    fprintf(stderr,"\t- port_num is the port to listen on\n");
    fprintf(stderr,"\t- ip_address is the ip address (in dotted\n");
    fprintf(stderr,"\t  decimal notation) to bind to. But it is not useful here...\n");
    fprintf(stderr,"\t- Hit Ctrl-C to terminate server program...\n");
    fprintf(stderr,"\t- The defaults are TCP, 2007 and INADDR_ANY.\n");
    WSACleanup();
    exit(1);
}

int main(int argc, char **argv)
{
    char Buffer[128];
    char *ip_address= NULL;
    unsigned short port=DEFAULT_PORT;
    int retval;
    int fromlen;
    int i;
    int socket_type = DEFAULT_PROTO;
    struct sockaddr_in local, from;
    WSADATA wsaData;
    SOCKET listen_socket, msgsock;

    /* Parse arguments, if there are arguments supplied */
    if (argc > 1)
       {
        for(i=1; i<argc; i++)
              {
                     // switches or options...
            if ((argv[i][0] == '-') || (argv[i][0] == '/'))
                     {
                            // Change to lower...if any
                           switch( tolower(argv[i][1]))
                           {
                     // if -p or /p
                    case 'p':
                        if (!stricmp(argv[i+1], "TCP"))
                            socket_type = SOCK_STREAM;
                        else if (!stricmp(argv[i+1], "UDP"))
                            socket_type = SOCK_DGRAM;
                        else
                            Usage(argv[0]);
                        i++;
                        break;
                     // if -i or /i, for server it is not so useful...
                    case 'i':
                        ip_address = argv[++i];
                        break;
                    // if -e or /e
                    case 'e':
                        port = atoi(argv[++i]);
                        break;
                     // No match...
                    default:
                        Usage(argv[0]);
                        break;
                }
            }
            else
                Usage(argv[0]);
        }
    }

    // Request Winsock version 2.2
    if ((retval = WSAStartup(0x202, &wsaData)) != 0)
       {
        fprintf(stderr,"Server: WSAStartup() failed with error %d\n", retval);
        WSACleanup();
        return -1;
    }
    else
       printf("Server: WSAStartup() is OK.\n");

    if (port == 0)
       {
        Usage(argv[0]);
    }

    local.sin_family = AF_INET;
    local.sin_addr.s_addr = (!ip_address) ? INADDR_ANY:inet_addr(ip_address);

    /* Port MUST be in Network Byte Order */
    local.sin_port = htons(port);
    // TCP socket
    listen_socket = socket(AF_INET, socket_type,0);

    if (listen_socket == INVALID_SOCKET){
        fprintf(stderr,"Server: socket() failed with error %d\n", WSAGetLastError());
        WSACleanup();
        return -1;
    }
    else
       printf("Server: socket() is OK.\n");

    // bind() associates a local address and port combination with the socket just created.
    // This is most useful when the application is a
    // server that has a well-known port that clients know about in advance.
    if (bind(listen_socket, (struct sockaddr*)&local, sizeof(local)) == SOCKET_ERROR)
       {
        fprintf(stderr,"Server: bind() failed with error %d\n", WSAGetLastError());
        WSACleanup();
        return -1;
    }
    else
              printf("Server: bind() is OK.\n");

     // So far, everything we did was applicable to TCP as well as UDP.
     // However, there are certain steps that do not work when the server is
     // using UDP. We cannot listen() on a UDP socket.
    if (socket_type != SOCK_DGRAM)
       {
        if (listen(listen_socket,5) == SOCKET_ERROR)
              {
            fprintf(stderr,"Server: listen() failed with error %d\n", WSAGetLastError());
            WSACleanup();
            return -1;
        }
       else
              printf("Server: listen() is OK.\n");
    }
    printf("Server: %s: I'm listening and waiting connection\non port %d, protocol %s\n", argv[0], port, (socket_type == SOCK_STREAM)?"TCP":"UDP");

       while(1)
       {
        fromlen =sizeof(from);
        // accept() doesn't make sense on UDP, since we do not listen()
        if (socket_type != SOCK_DGRAM)
              {
            msgsock = accept(listen_socket, (struct sockaddr*)&from, &fromlen);
            if (msgsock == INVALID_SOCKET)
           {
                fprintf(stderr,"Server: accept() error %d\n", WSAGetLastError());
                WSACleanup();
                return -1;
            }
           else
              printf("Server: accept() is OK.\n");
              printf("Server: accepted connection from %s, port %d\n", inet_ntoa(from.sin_addr), htons(from.sin_port)) ;

        }
        else
            msgsock = listen_socket;

        // In the case of SOCK_STREAM, the server can do recv() and send() on
        // the accepted socket and then close it.
        // However, for SOCK_DGRAM (UDP), the server will do recvfrom() and sendto()  in a loop.
        if (socket_type != SOCK_DGRAM)
            retval = recv(msgsock, Buffer, sizeof(Buffer), 0);

       else
       {
            retval = recvfrom(msgsock,Buffer, sizeof(Buffer), 0, (struct sockaddr *)&from, &fromlen);
            printf("Server: Received datagram from %s\n", inet_ntoa(from.sin_addr));
        }

        if (retval == SOCKET_ERROR)
              {
            fprintf(stderr,"Server: recv() failed: error %d\n", WSAGetLastError());
            closesocket(msgsock);
            continue;
        }
       else
            printf("Server: recv() is OK.\n");

        if (retval == 0)
              {
            printf("Server: Client closed connection.\n");
            closesocket(msgsock);
            continue;
        }
        printf("Server: Received %d bytes, data \"%s\" from client\n", retval, Buffer);

        printf("Server: Echoing the same data back to client...\n");
        if (socket_type != SOCK_DGRAM)
            retval = send(msgsock, Buffer, sizeof(Buffer), 0);
        else
            retval = sendto(msgsock, Buffer, sizeof(Buffer), 0, (struct sockaddr *)&from, fromlen);

              if (retval == SOCKET_ERROR)
              {
                     fprintf(stderr,"Server: send() failed: error %d\n", WSAGetLastError());
               }
              else
                     printf("Server: send() is OK.\n");

        if (socket_type != SOCK_DGRAM)
       {
            printf("Server: I'm waiting more connection, try running the client\n");
            printf("Server: program from the same computer or other computer...\n");
            closesocket(msgsock);
        }
        else
            printf("Server: UDP server looping back for more requests\n");
        continue;
    }
       return 0;
}

[S G H]

tolower is a function ( If i remind well it's in the ctype.h header? For C++ use cctype ) that converts upper-case characters to lower-case characters.
For example:

tolower('A'); returns 'a'.
tolower('c'); returns 'c'.

So at the beginning of your code try #include <cctype> .

Less On-Topic:
Also you may want to change your code to be more C++-Friendly.
Most C headers (stdio.h, stdlib.h...) have a C++-Friendly header, it's easy to find it out:
Remove the '.h' suffix and add a 'c' prefix.
So, stdio.h becomes cstdio, and stdlib.h becomes cstdlib.
Also string.h becomes cstring.
Windows.h doesn't have a secondary header, you can still hold it as it is.

In fact you should change from:

#include <stdlib.h>
#include <stdio.h>
#include <string.h> 

to:

#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <cctype> 

[devonrevenge]

nope nothing

[S G H]

What does the error say?

[devonrevenge]

The error says; "I hate you, learn java cos stupid people find it easier"

okay there was no error its just that it can either not know what tolower is or not reconise the other libraries/not link with them cos they have no header

[naraku9333]

You have to link to winsock32

[S G H]

devonrevenge wrote:

the error is on line 46

devonrevenge wrote:

okay there was no error its just that it can either not know what tolower is or not reconise [.....]

So, is there any error?
Because if 'it' didn't know what tolower was, you had an error. Also try with std::tolower.
For more details head over here: http://www.cplusplus.com/reference/cctype/tolower/

[devonrevenge]

ah okay, eill link to winsock32...thats linking a library on 'library path' right? then i right something like -lwinsock32 on other link options??

the error is something like unreconised function 'tolower'

and then with the changes it doesnt reconise every single non c++command

[modoran]

There is no such thing as "winsock2" library, the correct library name is libwsock32.a if you use MinGW or wsock32.lib if you use Microsoft compiler.


And please add this line to your program:
#include <ctype.h>

[devonrevenge]

it makes it worse strangely it says undefined reference to ... everything

[modoran]

As you seem to use MinGW, use these commands for compiling:

g++.exe -Wall -fexceptions -O2 -c C:\Users\george\Desktop\testconsole\main.cpp -o obj\Release\main.o
g++.exe -o bin\Release\testconsole.exe obj\Release\main.o -s -lwsock32

As you see, only -lwsock32 needs to be added to the linker. (or libwsock32.a)