stdin

Is it possible to set timeout for std::cin? For example, std::cin doesn't receive any data during 10 seconds - it throws an exception or returns an error. Edited: And what about timer from Boost library ? As far as I know, it is portable library. Is it possible to ask timer of Boost library to throw exceptions after predefined period of time? I guess it can solve this problem. It isn't possible to set a time out for std::cin in a portable way. Even when resorting to non-portable techniques, it isn't entirely trivial to do so: you will need to replace std::cin 's stream buffer. On a UNIX system

I'm seeking for ways to write data to the existing process's STDIN from external processes, and found similar question How do you stream data into the STDIN of a program from different local/remote processes in Python? in stackoverlow. In that thread, @Michael says that we can get file descriptors of existing process in path like below, and permitted to write data into them on Linux. /proc/$PID/fd/ So, I've created a simple script listed below to test writing data to the script's STDIN (and TTY ) from external process. #!/usr/bin/env python import os, sys def get_ttyname(): for f in sys.stdin,

Let's say I have this following bit of code in C: double var; scanf("%lf", &var); printf("%lf", var); printf("%f", var); It reads from stdin variable 'var' and then prints twice in stdout 'var'. I understand that's how you read a double variable from stdin, but my questions are: Why can you print a double with %lf? Why can you print a double with %f? Which one is better and correct to use? For variable argument functions like printf and scanf , the arguments are promoted, for example, any smaller integer types are promoted to int , float is promoted to double . scanf takes parameters of

Depending on command-line arguments, I'm setting a file pointer to point either towards a specified file or stdin (for the purpose of piping). I then pass this pointer around to a number of different functions to read from the file. Here is the function for getting the file pointer: FILE *getFile(int argc, char *argv[]) { FILE *myFile = NULL; if (argc == 2) { myFile = fopen(argv[1], "r"); if (myFile == NULL) fprintf(stderr, "File \"%s\" not found\n", argv[1]); } else myFile = stdin; return myFile; } When it's pointing to stdin, fseek does not seem to work. By that, I mean I use it and then use