Sending floating point number from server to client

Question

I am using TCP/IP socket programming. I have a floating point value stored in a variable ret_val in my server cod

Answer 1

Use a textual representation ?

char buf[32] ; 
snprintf(buf,sizeof buf,"%f",ret_val); 
write(fd,buf,strlen(buf));

You can read that string and parse it back again with sscanf. (Maybe even make it line terminated - "%f\n" - so you'll know when the number ends.)

The direct approach is to simply

write(fd,&ret_val,sizeof ret_val);

In both cases you should check the return value of write and take proper action if an error occurs, or write() wrote less bytes than you told it to.