Function setup_pager

pager.c:145–191

}

void setup_pager(struct repository *r)
{
	static int once = 0;
	const char *pager = git_pager(r, isatty(1));

	if (!pager)
		return;

	/*
	 * After we redirect standard output, we won't be able to use an ioctl
	 * to get the terminal size. Let's grab it now, and then set $COLUMNS
	 * to communicate it to any sub-processes.
	 */
	{
		char buf[64];
		xsnprintf(buf, sizeof(buf), "%d", term_columns());
		if (!term_columns_guessed)
			setenv("COLUMNS", buf, 0);
	}

	setenv("GIT_PAGER_IN_USE", "true", 1);

	child_process_init(&pager_process);

	/* spawn the pager */
	prepare_pager_args(&pager_process, pager);
	pager_process.in = -1;
	strvec_push(&pager_process.env, "GIT_PAGER_IN_USE");
	if (start_command(&pager_process))
		die("unable to execute pager '%s'", pager);

	/* original process continues, but writes to the pipe */
	old_fd1 = dup(1);
	dup2(pager_process.in, 1);
	if (isatty(2)) {
		old_fd2 = dup(2);
		dup2(pager_process.in, 2);
	}
	close(pager_process.in);

	sigchain_push_common(wait_for_pager_signal);

	if (!once) {
		once++;
		atexit(wait_for_pager_atexit);
	}
}

int pager_in_use(void)
{