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

Provide the required argument value after the option

%s: option requires an argument -- %c\n

Error message

%s: option requires an argument -- %c\n

What it means

Same 'option requires an argument' condition as error 24 but in the non-reentrant getopt code path (the _getopt_internal wrapper at line 956, not the _r reentrant variant at line 827). A short option marked with ':' in optstring was the last token. The non-reentrant variant sets c but does not return immediately, differing slightly from the reentrant path.

Source

Thrown at GPL/DemanglerGnu/src/demangler_gnu_v2_24/c/getopt.c:956

	      optarg = NULL;
	    nextchar = NULL;
	  }
	else
	  {
	    /* This is an option that requires an argument.  */
	    if (*nextchar != '\0')
	      {
		optarg = nextchar;
		/* If we end this ARGV-element by taking the rest as an arg,
		   we must advance to the next element now.  */
		optind++;
	      }
	    else if (optind == argc)
	      {
		if (opterr)
		  {
		    /* 1003.2 specifies the format of this message.  */
		    fprintf (stderr,
			   _("%s: option requires an argument -- %c\n"),
			   argv[0], c);
		  }
		optopt = c;
		if (optstring[0] == ':')
		  c = ':';
		else
		  c = '?';
	      }
	    else
	      /* We already incremented `optind' once;
		 increment it again when taking next ARGV-elt as argument.  */
	      optarg = argv[optind++];
	    nextchar = NULL;
	  }
      }
    return c;
  }

View on GitHub (pinned to d5f144c24d)

Solutions

Provide the required argument value after the option
Check that shell quoting preserves the argument
Restructure the command to avoid trailing required-arg options

Example fix

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

Defensive patterns

Strategy: validation

Validate before calling

// Pre-check: ensure no trailing option-requiring-argument is left without a value
static int no_trailing_missing_arg(int argc, char *const argv[], const char *optstring) {
    if (argc < 1) return 1;
    const char *last = argv[argc - 1];
    if (last[0] == '-' && last[1] != '-') {
        char last_char = last[strlen(last) - 1];
        char *pos = strchr(optstring, last_char);
        if (pos && pos[1] == ':') return 0; // trailing option needs arg
    }
    return 1;
}

Try / catch

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

Prevention

Always supply argument values immediately after options that require them
Use --opt=value syntax to avoid ambiguity
Set optstring[0] = ':' to get ':' return on missing arg for finer control

When it happens

Trigger: Tool calls the non-reentrant getopt()/getopt_long() rather than getopt_r(); user passes an argument-requiring short option as the final token; optind == argc. opterr is non-zero.

Common situations: Same as error 24: trailing option without its value. The distinction is internal to which getopt variant the tool links against.

Related errors

AI-assisted analysis of NationalSecurityAgency/ghidra@d5f144c24d (2026-08-14). Data as JSON: /api/errors/d3e314c12e2d9f2d. Report an issue: GitHub.