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clinuxsocketsfwrite

C - write to file faild when I put function fwrite() in a loop

I want to receive a file through a TCP socket on Linux. But I just get a empty file. However when I delete line 1 (while), anything will go okay. My code on server looks like this:

while(1) 
{ 



  FILE *fp = fopen(file_name, "w"); 
  if(NULL == fp) 
  { 
    printf("File:\t%s Can Not Open To Write\n", file_name); 
    exit(1); 
  } 

  bzero(buffer, BUFFER_SIZE); 
  int length = 0; 
  while((length = recv(new_server_socket_fd, buffer, BUFFER_SIZE, 0)) > 0) 
  { 

    if(fwrite(buffer, sizeof(char), length, fp) < length) 
    { 
      printf("File:\t%s Write Failed\n", file_name); 
      break; 
    } 
    bzero(buffer, BUFFER_SIZE); 
}

One thing I can make sure is that "if(fwrite(...))" do execude cause I put a putchar('a') out of if() and I can get some "a" on my screen. All data will be transfered through socket new_server_socket_fd

Solution

  • fclose the file before you return.