rvinterf: begin change to backslash escape output format Right now throughout the rvinterf suite, any time we emit output that is expected to be ASCII, but may contain non-printable garbage, we use 'cat -v' form of garbage character representation. Unfortunately, this transformation is lossy (can't be reversed 100% reliably in the user's wetware), hence we would like to migrate to C-style backslash escapes, including doubling of any already-present backslashes - this escape mechanism is lossless. Begin this change by converting the output of RV and L1 traces in rvinterf and rvtdump.

/*
 * Both arguments to fc-cal2text must name directories that already exist.
 * Here we implement the check for this requirement.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

check_directory_exists(pathname)
	char *pathname;
{
	struct stat st;

	if (stat(pathname, &st) < 0) {
		perror(pathname);
		exit(1);
	}
	if (!S_ISDIR(st.st_mode)) {
		fprintf(stderr, "error: %s is not a directory\n", pathname);
		exit(1);
	}
	return(0);
}