What causes "%s: option `%s' requires an argument\n" in NationalSecurityAgency/ghidra?

Provide the required argument as the next token

%s: option `%s' requires an argument\n

Error message

%s: option `%s' requires an argument\n

What it means

A matched long option requires an argument (pfound->has_arg == 1) but optind >= argc — there is no following command-line token to consume. getopt reports the missing argument and returns ':' (if optstring starts with ':') or '?'.

Source

Thrown at GPL/DemanglerGnu/src/demangler_gnu_v2_41/c/getopt.c:733

			fprintf (stderr,
				 _("%s: option `%c%s' doesn't allow an argument\n"),
				 argv[0], argv[optind - 1][0], pfound->name);

		      nextchar += strlen (nextchar);

		      optopt = pfound->val;
		      return '?';
		    }
		}
	    }
	  else if (pfound->has_arg == 1)
	    {
	      if (optind < argc)
		optarg = argv[optind++];
	      else
		{
		  if (opterr)
		    fprintf (stderr,
			   _("%s: option `%s' requires an argument\n"),
			   argv[0], argv[optind - 1]);
		  nextchar += strlen (nextchar);
		  optopt = pfound->val;
		  return optstring[0] == ':' ? ':' : '?';
		}
	    }
	  nextchar += strlen (nextchar);
	  if (longind != NULL)
	    *longind = option_index;
	  if (pfound->flag)
	    {
	      *(pfound->flag) = pfound->val;
	      return 0;
	    }
	  return pfound->val;
	}

View on GitHub (pinned to d5f144c24d)

Solutions

Provide the required argument as the next token
Use `--option=value` syntax for clarity
Fix shell quoting around the argument

Example fix

// before
./c++filt --style
// after
./c++filt --style gnu-v3

Defensive patterns

Strategy: validation

Validate before calling

// Check that long options requiring an argument have a following value
static int validate_required_long_args(int argc, char *const argv[], const struct option *longopts) {
    for (int i = 1; i < argc; i++) {
        if (argv[i][0] != '-' || argv[i][1] != '-') continue;
        const char *name = argv[i] + 2;
        const char *eq = strchr(name, '=');
        size_t len = eq ? (size_t)(eq - name) : strlen(name);
        for (const struct option *o = longopts; o->name; o++) {
            if (strncmp(o->name, name, len) == 0 && strlen(o->name) == len) {
                if (o->has_arg == 1 && !eq && i + 1 >= argc) return 0;
                break;
            }
        }
    }
    return 1;
}

Try / catch

int c;
while ((c = getopt_long(argc, argv, optstring, longopts, NULL)) != -1) {
    if (c == '?' || c == ':') { exit(EXIT_FAILURE); }
}

Prevention

Always provide a value for argument-requiring long options
Use --option=value syntax for explicit binding
Use optstring starting with ':' to distinguish missing-arg from invalid-opt

When it happens

Trigger: User passes `--requirearg` as the last token where that option has has_arg == 1; optind == argc so no next argument exists. opterr is non-zero.

Common situations: Trailing long option that needs a value with none provided; shell quoting that dropped the argument; script logic that conditionally adds the option without its value.

Related errors

AI-assisted analysis of NationalSecurityAgency/ghidra@d5f144c24d (2026-08-14). Data as JSON: /api/errors/f5349f127ec5d6e8. Report an issue: GitHub.