Comments by ayesha hassan (Top 56 by date)

even "r+b" is working fine. Can you explain a little further why do you prefer "rb"?

while(fpSend!=NULL)
{
int bytes_read=0;
if((bytes_read=fread(file_buffer, 1,12, fpSend))<=0)
{
if(feof(fpSend))
{
//"End of File Found";
return 0;
}
else
{
//"fread() failed"
return 0;
}
}
Is it what you meant?

I think this is going to work. Infact, Wouldn't it be better to read only fixed number of bytes using fread(), transfer them over the socket and then read the next bytes?
By the way, Thank you so much :)

Read one line from a text file using fgets() and stored it in char[] but what I get is corrupted data :(

I guess file format i.e. ".txt" is defined :(
The data types of the contents inside the file is not known. i.e file may have char as well as int.

@CPallini : Once again you have solved it :)

I am sorry for improper indentation. I am going to fix that :)

I got the idea now :)

OMG. When I was posting this question, I was dead sure that nobody is going to go through a code this long. I am shocked to see that people here are so helping that they spare their time to find out the stupid errors made by people like me :) I am really thankful for the help :)

+1, Problem Solved :)

+1. Thank you for the explanation

+1 for the help :) Thanks a lot

+1 for the help :) Thanks a lot

Thank you so much. It works now :)

I shifted towards the idea of using non blocking sockets when I realized that my Server is blocking in continuous call to recvfrom() and is unable to send anything even if it wants, unless call to recvfrom() ends.
e.g:
while(1)
{
if((recv_len = recvfrom(AH_glb_ackSocketIdentifier, receiveBuffer, sizeof(receiveBuffer), 0, (struct sockaddr *) &acksocket, &socketLength)) == SOCKET_ERROR)
{
//recvfrom() Failure.
}
if (sendto(socketIdentifier,sendBuffer,strlen(sendBuffer) , 0 , (struct sockaddr *) &AH_glb_connectedSocket, sizeof(AH_glb_connectedSocket)) == SOCKET_ERROR)
{
//sento() Failure
}
}

Thank you so much :) It is working now :)

Thank you so much for such an explanatory answer :)

Thank you so very much for the help :)

Thank you for the explanation :)

I have always followed the concept that multithreading can only be implemented on multiple processors system where there are more than one processor to be assigned to each thread and each thread can be executed simultaneoulsy. There is no scheduling in this case as each of the thread has separate resources all dedicated to it.
what is the difference between single processor and multiple processor systems then? :(
I have posted another question here http://www.codeproject.com/Questions/580778/Canplusmultithreadingplusbeplusimplementedplusonpl

If I have a single processor system and I can not implement multithreading, what am I supposed to do then in order to handle multiple clients in my server? :(

5.

5.

For that do I need one main receiving thread and distribute the incoming clients on the basis of their IP addresses to specific threads?

@jsolutions_uk : Thanks for sharing about receive queue. But upto what limit will the data be queued in such a buffer? There must be a limit after which the queue is full and moreincoming data will be discarded, if I'm not worng in understanding the concept.

but there is no connect() or listen() in UDP :(

Thank you so much. Your answer is really helpful, but the problem is that I am working on UDP and UDP does not listen(). listen() is avialable only in TCP as far as I know :(

If there is only a single thread and all of the 40 clients send data simultaneously on this single socket, there are chances that data of each client may get dropped.
Due to this reason, I shifted towards creating dedicated sockets for each client.

if data arrives from 40 clients at a socket, it will be buffered in socket buffer right? and each call to recvfrom() will read data from socket buffer

Thank you for the help, but this function changes the name of PC after the system is restarted while I want to change the name as soon as the function is called.

so I should copy only buffer[0] to buffer[byres_read-1] to some other new buffer and then send that new buffer over the socket?

still the same :(

and now the error:
error C2664: 'WriteFile' : cannot convert parameter 2 from 'int' to 'LPCVOID'

fpFile = fopen("sendclInformation.txt", "r+");
fseek(fpFile, 0, SEEK_SET);
WriteFile(file,EOF,strlen(EOF),&dwWritten,0);

I tried this but:
error C2664: 'strlen' : cannot convert parameter 1 from 'int' to 'const char *'

Below is the latest code that I am trying:
char ip[32];
int port;
DWORD dwWritten;
FILE *fpOriginal, *fpOutput;
HANDLE hFile,tempFile;
hFile=CreateFile("Hell.txt",GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,0,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,0);
tempFile=CreateFile("temp.txt",GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,0,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,0);
WriteFile(hFile,"10.0.1.25 524192\r\n\r\n10.0.1.25 524193\r\n\r\n",strlen("10.0.1.25 524192\r\n\r\n10.0.1.25 524193\r\n\r\n"),&dwWritten,0);
fpOriginal = fopen("Hell.txt", "r+");
fpOutput = fopen("temp.txt", "w+");

while (fscanf(fpOriginal, " %s %d", ip, &port) > 0)
{
printf("\nLine1:");
printf("ip: %s, port: %d", ip, port);
char portbuff[32], space[]=" ";
sprintf(portbuff, "%i",port);
strcat(ip," ");
strcat(ip,portbuff);
if(port == 524192)
printf("\n Delete this Line now");
else
WriteFile(tempFile,ip,strlen(ip),&dwWritten,0);
}

fclose(fpOriginal);
fclose(fpOutput);
CloseHandle(hFile);
CloseHandle(tempFile);
remove("Hell.txt");
if(!(rename("temp.txt","Bye.txt")))
{
printf("\ncould not rename\n");
}
else
printf("\nRename Done\n");
//remove ("Hell.txt");

And now another issue, sometimes, rename() fails as well, once in twenty tries.

I see two strange behaviours here.
1. Placing remove() before rename() gives an error while rename()ing the file.
2. Placing remove() after rename() does not rename the file but generates a new file :\

Could it be an issue due to the attributes I used while using CreateFile()?

Thank you :) I closed the file, then checked. even the rename() function succeeds still the file is not renamed or deleted :(

Updated my question for you :)

I know its all my mistake posting a stupid question + the typo.
I am really sorry :(

Thank you so much CPallini.
I followed your instructions and worte this code. Now the line I wanted to delete is successfully removed in my output file, but the last step of deleting the original file and renaming the output file is not working. Please tell me what wrong am I doing.
char ip[32];
int port;
DWORD dwWritten;
FILE *fp;
HANDLE hFile,tempFile;
hFile=CreateFile("Hell.txt",GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,0,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,0);
tempFile=CreateFile("temp.txt",GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,0,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,0);
WriteFile(hFile,"10.0.1.25 524192\r\n\r\n10.0.1.25 524193\r\n\r\n",strlen("10.0.1.25 524192\r\n\r\n10.0.1.25 524193\r\n\r\n"),&dwWritten,0);
fp = fopen("Hell.txt", "r+");

while (fscanf(fp, " %s %d", ip, &port) > 0)
{
printf("\nLine1:");
printf("ip: %s, port: %d", ip, port);
char portbuff[32], space[]=" ";
sprintf(portbuff, "%i",port);
strcat(ip," ");
strcat(ip,portbuff);
if(port == 524192)
printf("\n Delete this Line now");
else
WriteFile(tempFile,ip,strlen(ip),&dwWritten,0);
}

remove ("Hell.txt");
rename("temp.txt","Hell.txt");

Thank you so much. looks useful to me but sounds complex :( I am new in this, can you give me an example?

Thank you so much :)

I am creating a .txt file for this purpose. Is it right ?

Your posts are always very helpful :)
Thanks alot again Matthew Faithfull :)

I preffer using single Sokcet and one thread for recvfrom() receiving data from all clients and 40 threads fro procssing this data. What do you suggest now?

Thank you everyone for the help, but since I am beginner in this, I am a little confused that waht happens if I create 40 threads and few of the thread try to write at the socket simultaneously? (Since there is only one socket for data reception and sending)

What have you tried so far? Do you have any piece of code that you tried? Please share that as well.