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https://linux.die.net/man/3/stderr https://linux.die.net/man/3/stderr Notes The stream stderr is unbuffered. The stream stdout is line-buffered when it points
by satiated_grue 3y ago
https://linux.die.net/man/3/stderr https://linux.die.net/man/3/stderr
Notes
The stream stderr is unbuffered. The stream stdout is line-buffered when it points to a terminal. Partial lines will not appear until fflush(3) or exit(3) is called, or a newline is printed. This can produce unexpected results, especially with debugging output. The buffering mode of the standard streams (or any other stream) can be changed using the setbuf(3) or setvbuf(3) call. Note that in case stdin is associated with a terminal, there may also be input buffering in the terminal driver, entirely unrelated to stdio buffering. (Indeed, normally terminal input is line buffered in the kernel.) This kernel input handling can be modified using calls like tcsetattr(3); see also stty(1), and termios(3).
- nerdponx 3y agoIs this a Linux implementation detail, or is it a feature of POSIX systems generally?
- thesuitonym 3y agoOpenBSD's stderr seems to be buffered, so it may just be a Linux thing. https://man.openbsd.org/stdio.3 https://man.openbsd.org/stdio.3
- loeg 3y agoThat page says the opposite: > Initially, the standard error stream is unbuffered.
- thesuitonym 3y agoI have no idea how I read that so wrong. Mea culpa.
- loeg 3y agoPOSIX says that stderr shouldn't be "fully buffered" https://pubs.opengroup.org/onlinepubs/9699919799/functions/stdin.html https://pubs.opengroup.org/onlinepubs/9699919799/functions/s... but I believe that allows for line buffering. Its terminology can be found here: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/stdio.h.html https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/st... (look for _IOFBF).