[derefr]

Isn't the output stream at least guaranteed to be flushed once on completion of the program, though?

[djcapelis]

Yes, it flushes completely outputting all characters. None of which contain a newline.

Flushing doesn't automatically add newlines for you in C. It flushes the buffers you gave it, it doesn't make new stuff up to print out along with your buffers.

[derefr]

(Right, I didn't mean to suggest it added a newline; just that adding a newline flushes the buffer, which was one half of the problem with missing a newline—but that if this is the only line of the program, this half of the problem is obviated.)

[getsat]

Adding a newline doesn't flush anything. You'd want to call fflush() to do that.

[bremac]

printf prints to standard output, which is line-buffered by default when reading from a tty on UNIX variants. This can lead to strange problems for those who try to use it to track which parts of a program are being executed, as demonstrated by the following program with an infinite loop:

  #include <stdio.h>
  int main(int c, char **v) {
    printf("Hello\nJello");
    while(1) ;
    return 0;
  }

[getsat]

Yes. You're not agreeing or disagreeing with me. Did you reply to the wrong post?

Also, using printf() for debugging? In 2011? I seriously hope you guys don't do this.

[jimbokun]

"Also, using printf() for debugging? In 2011? I seriously hope you guys don't do this."

OK, I'll bite. I haven't done any serious straight up C programming in over a decade, and yes, I used a lot of printf for debugging back then. What's the best way to debug C programs now? (I imagine printf wasn't the best way to debug programs when I was writing C, either.) A different logging library? gdb?

[bremac]

Adding a newline into a line buffer (which is a user-space buffer) flushes the buffered data up to and including the newline. fflush also flushes a user space buffer. Also, the "for those" implies I'm talking about someone else, not myself.