Bastian Ruppert wrote: > under Linux stdin is line buffered, More precisely, it's line buffered if stdin is a tty, fully-buffered otherwise. > that means you can read one byte with > following statement: > > read(0,&myvar,1); > > You get the byte after typing one or more chars AND return. > > But i need this function to return after every char entered in stdin. > > Is there a function that reads stdin without line buffering? User-space buffering of a stream (i.e. a "FILE *") can be controlled with setvbuf() (or the other functions described in the setvbuf(3) manpage). However, the terminal driver also performs line-buffering by default (so that you can edit the current line with Backspace, Ctrl-W, Ctrl-U). This can be disabled with tcsetattr() (see ern0's reply for details), although this also disables the use of Ctrl-D to generate EOF. > Is it possible to disable the linebuffer or to reduce the buffersize to one? > Does this kind of manupilation have consequences for the hole system or > just for the app doing this? setvbuf() only applies to a specific process. tcsetattr() affects the terminal device, so you must restore the state upon termination (both normal termination via exit() or return from main(), and abnormal termination via a signal), upon suspension (i.e. SIGTSTP; you can't catch SIGSTOP), or if you invoke a child process (via e.g. system()) which might need to use the terminal. -- Glynn Clements <glynn@xxxxxxxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
