CODEWITHSUNDEEP
network-programmingsizeoftcp
brknl
brknl

Reputation: 115

tcp send with its real length instead of using sizeof data

I am trying to send a small packet via tcp but i have a problem with the size of it. My data is 255 byte buffer:

buffer[0] = 0x00;
buffer[1] = 0x04;
buffer[2] = 0x06;
buffer[3] = 0x08;
buffer[4] = 0x01;
buffer[5] = 0x01;

and i use 

send(sockfd,buffer,6,MSG_NOSIGNAL|MSG_DONTWAIT);

but data can not be send when i use 6. If i use send like:

 send(sockfd,buffer,sizeof(buffer),MSG_NOSIGNAL|MSG_DONTWAIT);

then data is sent but recevier has to parse extra 250 0x00 byte and i don't want it. Why 6 is no ok. I also try 10 randomly nothing changes.

Here is my receiver code Anything writes at that side:

        while(1) {
           ret = recv(socket,buffer,sizeof(buffer),0);
           if (ret > 0) 
                 printf("recv success");
            else
            {
               if (ret == 0)
                   printf("recv failed (orderly shutdown)");
               else
                   printf("recv failed (errno:%d)",errno);
            }
        }

Upvotes: 0

Views: 96

Answers (1)

user207421
user207421

Reputation: 310913

Get rid of MSG_DONTWAIT. This is only useful when you have something else to do when the socket send buffer is full and the data can't be sent. As you aren't checking the result of send(), clearly you aren't interested in that condition. However you must check the result of send anyway, as you may have got an error, so fix your code to do that as well.

Upvotes: 2

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