Returns true if the named file exists and is a regular file.
/*
* call-seq:
* File.file?(file_name) => true or false
*
* Returns <code>true</code> if the named file exists and is a
* regular file.
*/
static VALUE
test_f(obj, fname)
VALUE obj, fname;
{
struct stat st;
if (rb_stat(fname, &st) < 0) return Qfalse;
if (S_ISREG(st.st_mode)) return Qtrue;
return Qfalse;
}