int fd = ret ? stdfderr : stdfdout;
fdprintf (fd, "usage: %s\n", progname);
fdprintf (fd, " -h : help message\n");
int fd = ret ? stdfderr : stdfdout;
fdprintf (fd, "usage: %s\n", progname);
fdprintf (fd, " -h : help message\n");
// test: echo "2 + * 3" | calc.exe | grep -q 'error'
// test: echo "sqrt 2" | calc.exe | grep -q 'error'
// test: echo "pow (2)" | calc.exe | grep -q 'error'
// test: echo "2 + * 3" | calc.exe | grep -q 'error'
// test: echo "sqrt 2" | calc.exe | grep -q 'error'
// test: echo "pow (2)" | calc.exe | grep -q 'error'