open_input
ifd = open_input(in);
ifd = open_input(in);
open_input(infile, define);
open_input(infile, define);
open_input(infile, define);
open_input(infile, define);
open_input(infile, define);
open_input(infile, define);
open_input(infile, define);
FILE *fp = open_input(src, (char *) 0);
tmp_fp = open_input(source_file, (char *) 0);
tmp_fp = open_input(source_file, my_altfile);