Introduce gdb_argv, a class wrapper for buildargv

This introduces gdb_argv, a class wrapping an "argv" pointer; that is,
a pointer to a NULL-terminated array of char*, where both the array
and each non-NULL element in the array are xmalloc'd.

This patch then changes most users of gdb_buildargv to use gdb_argv
instead.

ChangeLog
2017-08-03  Tom Tromey  <tom@tromey.com>

	* utils.h (struct gdb_argv_deleter): New.
	(gdb_argv): New class.
	* utils.c (gdb_argv::reset): New method.
	* tracepoint.c (delete_trace_variable_command): Use gdb_argv.
	* tracefile.c (tsave_command): Use gdb_argv.
	* top.c (new_ui_command): Use gdb_argv.
	* symmisc.c (maintenance_print_symbols)
	(maintenance_print_msymbols, maintenance_expand_symtabs): Use gdb_argv.
	* symfile.c (symbol_file_command, generic_load)
	(remove_symbol_file_command): Use gdb_argv.
	* stack.c (backtrace_command): Use gdb_argv.
	* source.c (add_path, show_substitute_path_command)
	(unset_substitute_path_command, set_substitute_path_command):
	Use gdb_argv.
	* skip.c (skip_command): Use gdb_argv.  Use gdb_buildargv.
	* ser-mingw.c (pipe_windows_open): Use gdb_argv.
	* remote.c (extended_remote_run, remote_put_command)
	(remote_get_command, remote_delete_command): Use gdb_argv.
	* remote-sim.c (gdbsim_load, gdbsim_create_inferior)
	(gdbsim_open): Use gdb_argv.
	* python/py-cmd.c (gdbpy_string_to_argv): Use gdb_argv.
	* psymtab.c (maintenance_print_psymbols): Use gdb_argv.
	* procfs.c (procfs_info_proc): Use gdb_argv.
	* interps.c (interpreter_exec_cmd): Use gdb_argv.
	* infrun.c (handle_command): Use gdb_argv.
	* inferior.c (add_inferior_command, clone_inferior_command):
	Use gdb_argv.
	* guile/scm-string.c (gdbscm_string_to_argv): Use gdb_argv.
	* exec.c (exec_file_command): Use gdb_argv.
	* cli/cli-cmds.c (alias_command): Use gdb_argv.
	* compile/compile.c (build_argc_argv): Use gdb_argv.

24 files changed, 289 insertions, 249 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 3136f49..392f58a 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,39 @@
 2017-08-03  Tom Tromey  <tom@tromey.com>
 
+	* utils.h (struct gdb_argv_deleter): New.
+	(gdb_argv): New class.
+	* utils.c (gdb_argv::reset): New method.
+	* tracepoint.c (delete_trace_variable_command): Use gdb_argv.
+	* tracefile.c (tsave_command): Use gdb_argv.
+	* top.c (new_ui_command): Use gdb_argv.
+	* symmisc.c (maintenance_print_symbols)
+	(maintenance_print_msymbols, maintenance_expand_symtabs): Use gdb_argv.
+	* symfile.c (symbol_file_command, generic_load)
+	(remove_symbol_file_command): Use gdb_argv.
+	* stack.c (backtrace_command): Use gdb_argv.
+	* source.c (add_path, show_substitute_path_command)
+	(unset_substitute_path_command, set_substitute_path_command):
+	Use gdb_argv.
+	* skip.c (skip_command): Use gdb_argv.  Use gdb_buildargv.
+	* ser-mingw.c (pipe_windows_open): Use gdb_argv.
+	* remote.c (extended_remote_run, remote_put_command)
+	(remote_get_command, remote_delete_command): Use gdb_argv.
+	* remote-sim.c (gdbsim_load, gdbsim_create_inferior)
+	(gdbsim_open): Use gdb_argv.
+	* python/py-cmd.c (gdbpy_string_to_argv): Use gdb_argv.
+	* psymtab.c (maintenance_print_psymbols): Use gdb_argv.
+	* procfs.c (procfs_info_proc): Use gdb_argv.
+	* interps.c (interpreter_exec_cmd): Use gdb_argv.
+	* infrun.c (handle_command): Use gdb_argv.
+	* inferior.c (add_inferior_command, clone_inferior_command):
+	Use gdb_argv.
+	* guile/scm-string.c (gdbscm_string_to_argv): Use gdb_argv.
+	* exec.c (exec_file_command): Use gdb_argv.
+	* cli/cli-cmds.c (alias_command): Use gdb_argv.
+	* compile/compile.c (build_argc_argv): Use gdb_argv.
+
+2017-08-03  Tom Tromey  <tom@tromey.com>
+
 	* python/python.c (gdbpy_decode_line): Use unique_xmalloc_ptr.
 
 2017-08-03  Tom Tromey  <tom@tromey.com>
diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
index a0d566b..036a2f0 100644
--- a/gdb/cli/cli-cmds.c
+++ b/gdb/cli/cli-cmds.c
@@ -1400,31 +1400,27 @@ alias_command (char *args, int from_tty)
 {
   int i, alias_argc, command_argc;
   int abbrev_flag = 0;
-  char *args2, *equals;
+  char *equals;
   const char *alias, *command;
-  char **alias_argv, **command_argv;
-  struct cleanup *cleanup;
 
   if (args == NULL || strchr (args, '=') == NULL)
     alias_usage_error ();
 
-  args2 = xstrdup (args);
-  cleanup = make_cleanup (xfree, args2);
-  equals = strchr (args2, '=');
-  *equals = '\0';
-  alias_argv = gdb_buildargv (args2);
-  make_cleanup_freeargv (alias_argv);
-  command_argv = gdb_buildargv (equals + 1);
-  make_cleanup_freeargv (command_argv);
+  equals = strchr (args, '=');
+  std::string args2 (args, equals - args);
+
+  gdb_argv built_alias_argv (args2.c_str ());
+  gdb_argv command_argv (equals + 1);
 
-  for (i = 0; alias_argv[i] != NULL; )
+  char **alias_argv = built_alias_argv.get ();
+  while (alias_argv[0] != NULL)
     {
-      if (strcmp (alias_argv[i], "-a") == 0)
+      if (strcmp (alias_argv[0], "-a") == 0)
 	{
 	  ++alias_argv;
 	  abbrev_flag = 1;
 	}
-      else if (strcmp (alias_argv[i], "--") == 0)
+      else if (strcmp (alias_argv[0], "--") == 0)
 	{
 	  ++alias_argv;
 	  break;
@@ -1449,12 +1445,13 @@ alias_command (char *args, int from_tty)
     }
 
   alias_argc = countargv (alias_argv);
-  command_argc = countargv (command_argv);
+  command_argc = command_argv.count ();
 
   /* COMMAND must exist.
      Reconstruct the command to remove any extraneous spaces,
      for better error messages.  */
-  std::string command_string (argv_to_string (command_argv, command_argc));
+  std::string command_string (argv_to_string (command_argv.get (),
+					      command_argc));
   command = command_string.c_str ();
   if (! valid_command_p (command))
     error (_("Invalid command to alias to: %s"), command);
@@ -1511,8 +1508,6 @@ alias_command (char *args, int from_tty)
 		     command_argv[command_argc - 1],
 		     class_alias, abbrev_flag, c_command->prefixlist);
     }
-
-  do_cleanups (cleanup);
 }
 
 /* Print a list of files and line numbers which a user may choose from
diff --git a/gdb/compile/compile.c b/gdb/compile/compile.c
index 5269aaf..bca7b57 100644
--- a/gdb/compile/compile.c
+++ b/gdb/compile/compile.c
@@ -285,15 +285,17 @@ get_expr_block_and_pc (CORE_ADDR *pc)
   return block;
 }
 
-/* Call gdb_buildargv, set its result for S into *ARGVP but calculate also the
-   number of parsed arguments into *ARGCP.  If gdb_buildargv has returned NULL
-   then *ARGCP is set to zero.  */
+/* Call buildargv (via gdb_argv), set its result for S into *ARGVP but
+   calculate also the number of parsed arguments into *ARGCP.  If
+   buildargv has returned NULL then *ARGCP is set to zero.  */
 
 static void
 build_argc_argv (const char *s, int *argcp, char ***argvp)
 {
-  *argvp = gdb_buildargv (s);
-  *argcp = countargv (*argvp);
+  gdb_argv args (s);
+
+  *argcp = args.count ();
+  *argvp = args.release ();
 }
 
 /* String for 'set compile-args' and 'show compile-args'.  */
@@ -517,7 +519,7 @@ compile_to_object (struct command_line *cmd, const char *cmd_string,
 
   /* Set compiler command-line arguments.  */
   get_args (compiler, gdbarch, &argc, &argv);
-  make_cleanup_freeargv (argv);
+  gdb_argv argv_holder (argv);
 
   error_message = compiler->fe->ops->set_arguments (compiler->fe, triplet_rx,
 						    argc, argv);
diff --git a/gdb/exec.c b/gdb/exec.c
index 05ecb1b..6980b07 100644
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -407,7 +407,6 @@ exec_file_attach (const char *filename, int from_tty)
 static void
 exec_file_command (char *args, int from_tty)
 {
-  char **argv;
   char *filename;
 
   if (from_tty && target_has_execution
@@ -417,13 +416,11 @@ exec_file_command (char *args, int from_tty)
 
   if (args)
     {
-      struct cleanup *cleanups;
-
       /* Scan through the args and pick up the first non option arg
          as the filename.  */
 
-      argv = gdb_buildargv (args);
-      cleanups = make_cleanup_freeargv (argv);
+      gdb_argv built_argv (args);
+      char **argv = built_argv.get ();
 
       for (; (*argv != NULL) && (**argv == '-'); argv++)
         {;
@@ -431,11 +428,8 @@ exec_file_command (char *args, int from_tty)
       if (*argv == NULL)
         error (_("No executable file name was specified"));
 
-      filename = tilde_expand (*argv);
-      make_cleanup (xfree, filename);
-      exec_file_attach (filename, from_tty);
-
-      do_cleanups (cleanups);
+      gdb::unique_xmalloc_ptr<char> filename (tilde_expand (*argv));
+      exec_file_attach (filename.get (), from_tty);
     }
   else
     exec_file_attach (NULL, from_tty);
diff --git a/gdb/guile/scm-string.c b/gdb/guile/scm-string.c
index d97f583..4e495eb 100644
--- a/gdb/guile/scm-string.c
+++ b/gdb/guile/scm-string.c
@@ -241,7 +241,6 @@ static SCM
 gdbscm_string_to_argv (SCM string_scm)
 {
   char *string;
-  char **c_argv;
   int i;
   SCM result = SCM_EOL;
 
@@ -254,11 +253,10 @@ gdbscm_string_to_argv (SCM string_scm)
       return SCM_EOL;
     }
 
-  c_argv = gdb_buildargv (string);
-  for (i = 0; c_argv[i] != NULL; ++i)
-    result = scm_cons (gdbscm_scm_from_c_string (c_argv[i]), result);
+  gdb_argv c_argv (string);
+  for (char *arg : c_argv)
+    result = scm_cons (gdbscm_scm_from_c_string (arg), result);
 
-  freeargv (c_argv);
   xfree (string);
 
   return scm_reverse_x (result, SCM_EOL);
diff --git a/gdb/inferior.c b/gdb/inferior.c
index 8e8e13a..a20c6c5 100644
--- a/gdb/inferior.c
+++ b/gdb/inferior.c
@@ -795,20 +795,17 @@ static void
 add_inferior_command (char *args, int from_tty)
 {
   int i, copies = 1;
-  char *exec = NULL;
-  char **argv;
+  gdb::unique_xmalloc_ptr<char> exec;
   symfile_add_flags add_flags = 0;
-  struct cleanup *old_chain = make_cleanup (null_cleanup, NULL);
 
   if (from_tty)
     add_flags |= SYMFILE_VERBOSE;
 
   if (args)
     {
-      argv = gdb_buildargv (args);
-      make_cleanup_freeargv (argv);
+      gdb_argv built_argv (args);
 
-      for (; *argv != NULL; argv++)
+      for (char **argv = built_argv.get (); *argv != NULL; argv++)
 	{
 	  if (**argv == '-')
 	    {
@@ -824,8 +821,7 @@ add_inferior_command (char *args, int from_tty)
 		  ++argv;
 		  if (!*argv)
 		    error (_("No argument to -exec"));
-		  exec = tilde_expand (*argv);
-		  make_cleanup (xfree, exec);
+		  exec.reset (tilde_expand (*argv));
 		}
 	    }
 	  else
@@ -849,12 +845,10 @@ add_inferior_command (char *args, int from_tty)
 	  set_current_inferior (inf);
 	  switch_to_thread (null_ptid);
 
-	  exec_file_attach (exec, from_tty);
-	  symbol_file_add_main (exec, add_flags);
+	  exec_file_attach (exec.get (), from_tty);
+	  symbol_file_add_main (exec.get (), add_flags);
 	}
     }
-
-  do_cleanups (old_chain);
 }
 
 /* clone-inferior [-copies N] [ID] */
@@ -863,15 +857,13 @@ static void
 clone_inferior_command (char *args, int from_tty)
 {
   int i, copies = 1;
-  char **argv;
   struct inferior *orginf = NULL;
-  struct cleanup *old_chain = make_cleanup (null_cleanup, NULL);
 
   if (args)
     {
-      argv = gdb_buildargv (args);
-      make_cleanup_freeargv (argv);
+      gdb_argv built_argv (args);
 
+      char **argv = built_argv.get ();
       for (; *argv != NULL; argv++)
 	{
 	  if (**argv == '-')
@@ -942,8 +934,6 @@ clone_inferior_command (char *args, int from_tty)
       switch_to_thread (null_ptid);
       clone_program_space (pspace, orginf->pspace);
     }
-
-  do_cleanups (old_chain);
 }
 
 /* Print notices when new inferiors are created and die.  */
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 37ff015..8f966e2 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -8512,14 +8512,12 @@ sig_print_info (enum gdb_signal oursig)
 static void
 handle_command (char *args, int from_tty)
 {
-  char **argv;
   int digits, wordlen;
   int sigfirst, signum, siglast;
   enum gdb_signal oursig;
   int allsigs;
   int nsigs;
   unsigned char *sigs;
-  struct cleanup *old_chain;
 
   if (args == NULL)
     {
@@ -8534,24 +8532,23 @@ handle_command (char *args, int from_tty)
 
   /* Break the command line up into args.  */
 
-  argv = gdb_buildargv (args);
-  old_chain = make_cleanup_freeargv (argv);
+  gdb_argv built_argv (args);
 
   /* Walk through the args, looking for signal oursigs, signal names, and
      actions.  Signal numbers and signal names may be interspersed with
      actions, with the actions being performed for all signals cumulatively
      specified.  Signal ranges can be specified as <LOW>-<HIGH>.  */
 
-  while (*argv != NULL)
+  for (char *arg : built_argv)
     {
-      wordlen = strlen (*argv);
-      for (digits = 0; isdigit ((*argv)[digits]); digits++)
+      wordlen = strlen (arg);
+      for (digits = 0; isdigit (arg[digits]); digits++)
 	{;
 	}
       allsigs = 0;
       sigfirst = siglast = -1;
 
-      if (wordlen >= 1 && !strncmp (*argv, "all", wordlen))
+      if (wordlen >= 1 && !strncmp (arg, "all", wordlen))
 	{
 	  /* Apply action to all signals except those used by the
 	     debugger.  Silently skip those.  */
@@ -8559,37 +8556,37 @@ handle_command (char *args, int from_tty)
 	  sigfirst = 0;
 	  siglast = nsigs - 1;
 	}
-      else if (wordlen >= 1 && !strncmp (*argv, "stop", wordlen))
+      else if (wordlen >= 1 && !strncmp (arg, "stop", wordlen))
 	{
 	  SET_SIGS (nsigs, sigs, signal_stop);
 	  SET_SIGS (nsigs, sigs, signal_print);
 	}
-      else if (wordlen >= 1 && !strncmp (*argv, "ignore", wordlen))
+      else if (wordlen >= 1 && !strncmp (arg, "ignore", wordlen))
 	{
 	  UNSET_SIGS (nsigs, sigs, signal_program);
 	}
-      else if (wordlen >= 2 && !strncmp (*argv, "print", wordlen))
+      else if (wordlen >= 2 && !strncmp (arg, "print", wordlen))
 	{
 	  SET_SIGS (nsigs, sigs, signal_print);
 	}
-      else if (wordlen >= 2 && !strncmp (*argv, "pass", wordlen))
+      else if (wordlen >= 2 && !strncmp (arg, "pass", wordlen))
 	{
 	  SET_SIGS (nsigs, sigs, signal_program);
 	}
-      else if (wordlen >= 3 && !strncmp (*argv, "nostop", wordlen))
+      else if (wordlen >= 3 && !strncmp (arg, "nostop", wordlen))
 	{
 	  UNSET_SIGS (nsigs, sigs, signal_stop);
 	}
-      else if (wordlen >= 3 && !strncmp (*argv, "noignore", wordlen))
+      else if (wordlen >= 3 && !strncmp (arg, "noignore", wordlen))
 	{
 	  SET_SIGS (nsigs, sigs, signal_program);
 	}
-      else if (wordlen >= 4 && !strncmp (*argv, "noprint", wordlen))
+      else if (wordlen >= 4 && !strncmp (arg, "noprint", wordlen))
 	{
 	  UNSET_SIGS (nsigs, sigs, signal_print);
 	  UNSET_SIGS (nsigs, sigs, signal_stop);
 	}
-      else if (wordlen >= 4 && !strncmp (*argv, "nopass", wordlen))
+      else if (wordlen >= 4 && !strncmp (arg, "nopass", wordlen))
 	{
 	  UNSET_SIGS (nsigs, sigs, signal_program);
 	}
@@ -8602,11 +8599,11 @@ handle_command (char *args, int from_tty)
 	     SIGHUP, SIGINT, SIGALRM, etc. will work right anyway.  */
 
 	  sigfirst = siglast = (int)
-	    gdb_signal_from_command (atoi (*argv));
-	  if ((*argv)[digits] == '-')
+	    gdb_signal_from_command (atoi (arg));
+	  if (arg[digits] == '-')
 	    {
 	      siglast = (int)
-		gdb_signal_from_command (atoi ((*argv) + digits + 1));
+		gdb_signal_from_command (atoi (arg + digits + 1));
 	    }
 	  if (sigfirst > siglast)
 	    {
@@ -8618,7 +8615,7 @@ handle_command (char *args, int from_tty)
 	}
       else
 	{
-	  oursig = gdb_signal_from_name (*argv);
+	  oursig = gdb_signal_from_name (arg);
 	  if (oursig != GDB_SIGNAL_UNKNOWN)
 	    {
 	      sigfirst = siglast = (int) oursig;
@@ -8626,7 +8623,7 @@ handle_command (char *args, int from_tty)
 	  else
 	    {
 	      /* Not a number and not a recognized flag word => complain.  */
-	      error (_("Unrecognized or ambiguous flag word: \"%s\"."), *argv);
+	      error (_("Unrecognized or ambiguous flag word: \"%s\"."), arg);
 	    }
 	}
 
@@ -8664,8 +8661,6 @@ Are you sure you want to change it? "),
 	      break;
 	    }
 	}
-
-      argv++;
     }
 
   for (signum = 0; signum < nsigs; signum++)
@@ -8686,8 +8681,6 @@ Are you sure you want to change it? "),
 
 	break;
       }
-
-  do_cleanups (old_chain);
 }
 
 /* Complete the "handle" command.  */
diff --git a/gdb/interps.c b/gdb/interps.c
index 4de7c4e..1e59034 100644
--- a/gdb/interps.c
+++ b/gdb/interps.c
@@ -407,21 +407,14 @@ interpreter_exec_cmd (char *args, int from_tty)
 {
   struct ui_interp_info *ui_interp = get_current_interp_info ();
   struct interp *old_interp, *interp_to_use;
-  char **prules = NULL;
-  char **trule = NULL;
   unsigned int nrules;
   unsigned int i;
-  struct cleanup *cleanup;
 
   if (args == NULL)
     error_no_arg (_("interpreter-exec command"));
 
-  prules = gdb_buildargv (args);
-  cleanup = make_cleanup_freeargv (prules);
-
-  nrules = 0;
-  for (trule = prules; *trule != NULL; trule++)
-    nrules++;
+  gdb_argv prules (args);
+  nrules = prules.count ();
 
   if (nrules < 2)
     error (_("usage: interpreter-exec <interpreter> [ <command> ... ]"));
@@ -446,8 +439,6 @@ interpreter_exec_cmd (char *args, int from_tty)
     }
 
   interp_set (old_interp, 0);
-
-  do_cleanups (cleanup);
 }
 
 /* See interps.h.  */
diff --git a/gdb/procfs.c b/gdb/procfs.c
index b03809c..4b965ea 100644
--- a/gdb/procfs.c
+++ b/gdb/procfs.c
@@ -5100,7 +5100,6 @@ procfs_info_proc (struct target_ops *ops, const char *args,
   struct cleanup *old_chain;
   procinfo *process  = NULL;
   procinfo *thread   = NULL;
-  char    **argv     = NULL;
   char     *tmp      = NULL;
   int       pid      = 0;
   int       tid      = 0;
@@ -5121,24 +5120,19 @@ procfs_info_proc (struct target_ops *ops, const char *args,
     }
 
   old_chain = make_cleanup (null_cleanup, 0);
-  if (args)
-    {
-      argv = gdb_buildargv (args);
-      make_cleanup_freeargv (argv);
-    }
-  while (argv != NULL && *argv != NULL)
+  gdb_argv built_argv (args);
+  for (char *arg : argv)
     {
-      if (isdigit (argv[0][0]))
+      if (isdigit (arg[0]))
 	{
-	  pid = strtoul (argv[0], &tmp, 10);
+	  pid = strtoul (arg, &tmp, 10);
 	  if (*tmp == '/')
 	    tid = strtoul (++tmp, NULL, 10);
 	}
-      else if (argv[0][0] == '/')
+      else if (arg[0] == '/')
 	{
-	  tid = strtoul (argv[0] + 1, NULL, 10);
+	  tid = strtoul (arg + 1, NULL, 10);
 	}
-      argv++;
     }
   if (pid == 0)
     pid = ptid_get_pid (inferior_ptid);
diff --git a/gdb/psymtab.c b/gdb/psymtab.c
index 4077fb3..a3762b5 100644
--- a/gdb/psymtab.c
+++ b/gdb/psymtab.c
@@ -1905,7 +1905,6 @@ dump_psymtab_addrmap (struct objfile *objfile, struct partial_symtab *psymtab,
 static void
 maintenance_print_psymbols (char *args, int from_tty)
 {
-  char **argv;
   struct ui_file *outfile = gdb_stdout;
   struct cleanup *cleanups;
   char *address_arg = NULL, *source_arg = NULL, *objfile_arg = NULL;
@@ -1917,8 +1916,8 @@ maintenance_print_psymbols (char *args, int from_tty)
 
   dont_repeat ();
 
-  argv = gdb_buildargv (args);
-  cleanups = make_cleanup_freeargv (argv);
+  gdb_argv argv (args);
+  cleanups = make_cleanup (null_cleanup, NULL);
 
   for (i = 0; argv != NULL && argv[i] != NULL; ++i)
     {
diff --git a/gdb/python/py-cmd.c b/gdb/python/py-cmd.c
index b9f6037..2a7c613 100644
--- a/gdb/python/py-cmd.c
+++ b/gdb/python/py-cmd.c
@@ -775,22 +775,16 @@ gdbpy_string_to_argv (PyObject *self, PyObject *args)
 
   if (*input != '\0')
     {
-      char **c_argv = gdb_buildargv (input);
-      int i;
+      gdb_argv c_argv (input);
 
-      for (i = 0; c_argv[i] != NULL; ++i)
+      for (char *arg : c_argv)
 	{
-	  gdbpy_ref<> argp (PyString_FromString (c_argv[i]));
+	  gdbpy_ref<> argp (PyString_FromString (arg));
 
 	  if (argp == NULL
 	      || PyList_Append (py_argv.get (), argp.get ()) < 0)
-	    {
-	      freeargv (c_argv);
-	      return NULL;
-	    }
+	    return NULL;
 	}
-
-      freeargv (c_argv);
     }
 
   return py_argv.release ();
diff --git a/gdb/remote-sim.c b/gdb/remote-sim.c
index 508e2c2..75b1f56 100644
--- a/gdb/remote-sim.c
+++ b/gdb/remote-sim.c
@@ -570,8 +570,7 @@ gdbsim_load (struct target_ops *self, const char *args, int fromtty)
   if (args == NULL)
       error_no_arg (_("program to load"));
 
-  argv = gdb_buildargv (args);
-  make_cleanup_freeargv (argv);
+  gdb_argv argv (args);
 
   prog = tilde_expand (argv[0]);
 
@@ -609,7 +608,7 @@ gdbsim_create_inferior (struct target_ops *target, const char *exec_file,
   struct sim_inferior_data *sim_data
     = get_sim_inferior_data (current_inferior (), SIM_INSTANCE_NEEDED);
   int len;
-  char *arg_buf, **argv;
+  char *arg_buf;
   const char *args = allargs.c_str ();
 
   if (exec_file == 0 || exec_bfd == 0)
@@ -628,6 +627,7 @@ gdbsim_create_inferior (struct target_ops *target, const char *exec_file,
   remove_breakpoints ();
   init_wait_for_inferior ();
 
+  gdb_argv built_argv;
   if (exec_file != NULL)
     {
       len = strlen (exec_file) + 1 + allargs.size () + 1 + /*slop */ 10;
@@ -636,16 +636,14 @@ gdbsim_create_inferior (struct target_ops *target, const char *exec_file,
       strcat (arg_buf, exec_file);
       strcat (arg_buf, " ");
       strcat (arg_buf, args);
-      argv = gdb_buildargv (arg_buf);
-      make_cleanup_freeargv (argv);
+      built_argv.reset (arg_buf);
     }
-  else
-    argv = NULL;
 
   if (!have_inferiors ())
     init_thread_list ();
 
-  if (sim_create_inferior (sim_data->gdbsim_desc, exec_bfd, argv, env)
+  if (sim_create_inferior (sim_data->gdbsim_desc, exec_bfd,
+			   built_argv.get (), env)
       != SIM_RC_OK)
     error (_("Unable to create sim inferior."));
 
@@ -728,18 +726,21 @@ gdbsim_open (const char *args, int from_tty)
       strcat (arg_buf, " ");	/* 1 */
       strcat (arg_buf, args);
     }
-  sim_argv = gdb_buildargv (arg_buf);
+
+  gdb_argv args (arg_buf);
+  sim_argv = args.get ();
 
   init_callbacks ();
   gdbsim_desc = sim_open (SIM_OPEN_DEBUG, &gdb_callback, exec_bfd, sim_argv);
 
   if (gdbsim_desc == 0)
     {
-      freeargv (sim_argv);
       sim_argv = NULL;
       error (_("unable to create simulator instance"));
     }
 
+  args.release ();
+
   /* Reset the pid numberings for this batch of sim instances.  */
   next_pid = INITIAL_PID;
 
diff --git a/gdb/remote.c b/gdb/remote.c
index 5adf5eb..ff59a0f 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -9519,12 +9519,9 @@ extended_remote_run (const std::string &args)
 
   if (!args.empty ())
     {
-      struct cleanup *back_to;
       int i;
-      char **argv;
 
-      argv = gdb_buildargv (args.c_str ());
-      back_to = make_cleanup_freeargv (argv);
+      gdb_argv argv (args.c_str ());
       for (i = 0; argv[i] != NULL; i++)
 	{
 	  if (strlen (argv[i]) * 2 + 1 + len >= get_remote_packet_size ())
@@ -9533,7 +9530,6 @@ extended_remote_run (const std::string &args)
 	  len += 2 * bin2hex ((gdb_byte *) argv[i], rs->buf + len,
 			      strlen (argv[i]));
 	}
-      do_cleanups (back_to);
     }
 
   rs->buf[len++] = '\0';
@@ -12043,58 +12039,40 @@ remote_file_delete (const char *remote_file, int from_tty)
 static void
 remote_put_command (char *args, int from_tty)
 {
-  struct cleanup *back_to;
-  char **argv;
-
   if (args == NULL)
     error_no_arg (_("file to put"));
 
-  argv = gdb_buildargv (args);
-  back_to = make_cleanup_freeargv (argv);
+  gdb_argv argv (args);
   if (argv[0] == NULL || argv[1] == NULL || argv[2] != NULL)
     error (_("Invalid parameters to remote put"));
 
   remote_file_put (argv[0], argv[1], from_tty);
-
-  do_cleanups (back_to);
 }
 
 static void
 remote_get_command (char *args, int from_tty)
 {
-  struct cleanup *back_to;
-  char **argv;
-
   if (args == NULL)
     error_no_arg (_("file to get"));
 
-  argv = gdb_buildargv (args);
-  back_to = make_cleanup_freeargv (argv);
+  gdb_argv argv (args);
   if (argv[0] == NULL || argv[1] == NULL || argv[2] != NULL)
     error (_("Invalid parameters to remote get"));
 
   remote_file_get (argv[0], argv[1], from_tty);
-
-  do_cleanups (back_to);
 }
 
 static void
 remote_delete_command (char *args, int from_tty)
 {
-  struct cleanup *back_to;
-  char **argv;
-
   if (args == NULL)
     error_no_arg (_("file to delete"));
 
-  argv = gdb_buildargv (args);
-  back_to = make_cleanup_freeargv (argv);
+  gdb_argv argv (args);
   if (argv[0] == NULL || argv[1] != NULL)
     error (_("Invalid parameters to remote delete"));
 
   remote_file_delete (argv[0], from_tty);
-
-  do_cleanups (back_to);
 }
 
 static void
diff --git a/gdb/ser-mingw.c b/gdb/ser-mingw.c
index 3f12458..0b78ba1 100644
--- a/gdb/ser-mingw.c
+++ b/gdb/ser-mingw.c
@@ -863,20 +863,18 @@ pipe_windows_open (struct serial *scb, const char *name)
 {
   struct pipe_state *ps;
   FILE *pex_stderr;
-  char **argv;
   struct cleanup *back_to;
 
   if (name == NULL)
     error_no_arg (_("child command"));
 
-  argv = gdb_buildargv (name);
-  back_to = make_cleanup_freeargv (argv);
+  gdb_argv argv (name);
 
   if (! argv[0] || argv[0][0] == '\0')
     error (_("missing child command"));
 
   ps = make_pipe_state ();
-  make_cleanup (cleanup_pipe_state, ps);
+  back_to = make_cleanup (cleanup_pipe_state, ps);
 
   ps->pex = pex_init (PEX_USE_PIPES, "target remote pipe", NULL);
   if (! ps->pex)
@@ -890,7 +888,7 @@ pipe_windows_open (struct serial *scb, const char *name)
     const char *err_msg
       = pex_run (ps->pex, PEX_SEARCH | PEX_BINARY_INPUT | PEX_BINARY_OUTPUT
 		 | PEX_STDERR_TO_PIPE,
-                 argv[0], argv, NULL, NULL,
+                 argv[0], argv.get (), NULL, NULL,
                  &err);
 
     if (err_msg)
@@ -920,6 +918,7 @@ pipe_windows_open (struct serial *scb, const char *name)
 
   scb->state = (void *) ps;
 
+  argv.release ();
   discard_cleanups (back_to);
   return 0;
 
diff --git a/gdb/skip.c b/gdb/skip.c
index afa81ec..bf44913 100644
--- a/gdb/skip.c
+++ b/gdb/skip.c
@@ -217,8 +217,6 @@ skip_command (char *arg, int from_tty)
   const char *gfile = NULL;
   const char *function = NULL;
   const char *rfunction = NULL;
-  char **argv;
-  struct cleanup *cleanups;
   struct skiplist_entry *e;
   int i;
 
@@ -228,8 +226,7 @@ skip_command (char *arg, int from_tty)
       return;
     }
 
-  argv = buildargv (arg);
-  cleanups = make_cleanup_freeargv (argv);
+  gdb_argv argv (arg);
 
   for (i = 0; argv[i] != NULL; ++i)
     {
@@ -276,7 +273,6 @@ skip_command (char *arg, int from_tty)
 	     FUNCTION-NAME may be `foo (int)', and therefore we pass the
 	     complete original arg to skip_function command as if the user
 	     typed "skip function arg".  */
-	  do_cleanups (cleanups);
 	  skip_function_command (arg, from_tty);
 	  return;
 	}
@@ -336,8 +332,6 @@ skip_command (char *arg, int from_tty)
 			 lower_file_text, file_to_print);
       }
   }
-
-  do_cleanups (cleanups);
 }
 
 static void
diff --git a/gdb/source.c b/gdb/source.c
index 4cc862c..5473103 100644
--- a/gdb/source.c
+++ b/gdb/source.c
@@ -484,16 +484,12 @@ add_path (char *dirname, char **which_path, int parse_separators)
 
   if (parse_separators)
     {
-      char **argv, **argvp;
-
       /* This will properly parse the space and tab separators
 	 and any quotes that may exist.  */
-      argv = gdb_buildargv (dirname);
-
-      for (argvp = argv; *argvp; argvp++)
-	dirnames_to_char_ptr_vec_append (&dir_vec, *argvp);
+      gdb_argv argv (dirname);
 
-      freeargv (argv);
+      for (char *arg : argv)
+	dirnames_to_char_ptr_vec_append (&dir_vec, arg);
     }
   else
     VEC_safe_push (char_ptr, dir_vec, xstrdup (dirname));
@@ -1883,12 +1879,9 @@ static void
 show_substitute_path_command (char *args, int from_tty)
 {
   struct substitute_path_rule *rule = substitute_path_rules;
-  char **argv;
   char *from = NULL;
-  struct cleanup *cleanup;
   
-  argv = gdb_buildargv (args);
-  cleanup = make_cleanup_freeargv (argv);
+  gdb_argv argv (args);
 
   /* We expect zero or one argument.  */
 
@@ -1912,8 +1905,6 @@ show_substitute_path_command (char *args, int from_tty)
         printf_filtered ("  `%s' -> `%s'.\n", rule->from, rule->to);
       rule = rule->next;
     }
-
-  do_cleanups (cleanup);
 }
 
 /* Implement the "unset substitute-path" command.  */
@@ -1922,14 +1913,12 @@ static void
 unset_substitute_path_command (char *args, int from_tty)
 {
   struct substitute_path_rule *rule = substitute_path_rules;
-  char **argv = gdb_buildargv (args);
+  gdb_argv argv (args);
   char *from = NULL;
   int rule_found = 0;
-  struct cleanup *cleanup;
 
   /* This function takes either 0 or 1 argument.  */
 
-  cleanup = make_cleanup_freeargv (argv);
   if (argv != NULL && argv[0] != NULL && argv[1] != NULL)
     error (_("Incorrect usage, too many arguments in command"));
 
@@ -1967,8 +1956,6 @@ unset_substitute_path_command (char *args, int from_tty)
     error (_("No substitution rule defined for `%s'"), from);
 
   forget_cached_source_info ();
-
-  do_cleanups (cleanup);
 }
 
 /* Add a new source path substitution rule.  */
@@ -1976,12 +1963,9 @@ unset_substitute_path_command (char *args, int from_tty)
 static void
 set_substitute_path_command (char *args, int from_tty)
 {
-  char **argv;
   struct substitute_path_rule *rule;
-  struct cleanup *cleanup;
   
-  argv = gdb_buildargv (args);
-  cleanup = make_cleanup_freeargv (argv);
+  gdb_argv argv (args);
 
   if (argv == NULL || argv[0] == NULL || argv [1] == NULL)
     error (_("Incorrect usage, too few arguments in command"));
@@ -2008,8 +1992,6 @@ set_substitute_path_command (char *args, int from_tty)
 
   add_substitute_path_rule (argv[0], argv[1]);
   forget_cached_source_info ();
-
-  do_cleanups (cleanup);
 }
 
 
diff --git a/gdb/stack.c b/gdb/stack.c
index 7f8a51c..3e9dca2 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -1877,8 +1877,8 @@ backtrace_command (char *arg, int from_tty)
       char **argv;
       int i;
 
-      argv = gdb_buildargv (arg);
-      make_cleanup_freeargv (argv);
+      gdb_argv built_argv (arg);
+      argv = built_argv.get ();
       argc = 0;
       for (i = 0; argv[i]; i++)
 	{
diff --git a/gdb/symfile.c b/gdb/symfile.c
index 9cbd6e5..67a3976 100644
--- a/gdb/symfile.c
+++ b/gdb/symfile.c
@@ -1639,7 +1639,6 @@ symbol_file_command (char *args, int from_tty)
     }
   else
     {
-      char **argv = gdb_buildargv (args);
       objfile_flags flags = OBJF_USERLOADED;
       symfile_add_flags add_flags = 0;
       struct cleanup *cleanups;
@@ -1648,26 +1647,22 @@ symbol_file_command (char *args, int from_tty)
       if (from_tty)
 	add_flags |= SYMFILE_VERBOSE;
 
-      cleanups = make_cleanup_freeargv (argv);
-      while (*argv != NULL)
+      gdb_argv built_argv (args);
+      for (char *arg : built_argv)
 	{
-	  if (strcmp (*argv, "-readnow") == 0)
+	  if (strcmp (arg, "-readnow") == 0)
 	    flags |= OBJF_READNOW;
-	  else if (**argv == '-')
-	    error (_("unknown option `%s'"), *argv);
+	  else if (*arg == '-')
+	    error (_("unknown option `%s'"), arg);
 	  else
 	    {
-	      symbol_file_add_main_1 (*argv, add_flags, flags);
-	      name = *argv;
+	      symbol_file_add_main_1 (arg, add_flags, flags);
+	      name = arg;
 	    }
-
-	  argv++;
 	}
 
       if (name == NULL)
 	error (_("no symbol file name was specified"));
-
-      do_cleanups (cleanups);
     }
 }
 
@@ -2061,25 +2056,23 @@ void
 generic_load (const char *args, int from_tty)
 {
   char *filename;
-  struct cleanup *old_cleanups = make_cleanup (null_cleanup, 0);
+  struct cleanup *old_cleanups;
   struct load_section_data cbdata;
   struct load_progress_data total_progress;
   struct ui_out *uiout = current_uiout;
 
   CORE_ADDR entry;
-  char **argv;
 
   memset (&cbdata, 0, sizeof (cbdata));
   memset (&total_progress, 0, sizeof (total_progress));
   cbdata.progress_data = &total_progress;
 
-  make_cleanup (clear_memory_write_data, &cbdata.requests);
+  old_cleanups = make_cleanup (clear_memory_write_data, &cbdata.requests);
 
   if (args == NULL)
     error_no_arg (_("file to load"));
 
-  argv = gdb_buildargv (args);
-  make_cleanup_freeargv (argv);
+  gdb_argv argv (args);
 
   filename = tilde_expand (argv[0]);
   make_cleanup (xfree, filename);
@@ -2227,7 +2220,6 @@ add_symbol_file_command (char *args, int from_tty)
   int i;
   int expecting_sec_name = 0;
   int expecting_sec_addr = 0;
-  char **argv;
   struct objfile *objf;
   objfile_flags flags = OBJF_USERLOADED | OBJF_SHARED;
   symfile_add_flags add_flags = 0;
@@ -2254,8 +2246,7 @@ add_symbol_file_command (char *args, int from_tty)
   if (args == NULL)
     error (_("add-symbol-file takes a file name and an address"));
 
-  argv = gdb_buildargv (args);
-  make_cleanup_freeargv (argv);
+  gdb_argv argv (args);
 
   for (arg = argv[0], argcnt = 0; arg != NULL; arg = argv[++argcnt])
     {
@@ -2375,7 +2366,6 @@ add_symbol_file_command (char *args, int from_tty)
 static void
 remove_symbol_file_command (char *args, int from_tty)
 {
-  char **argv;
   struct objfile *objf = NULL;
   struct cleanup *my_cleanups;
   struct program_space *pspace = current_program_space;
@@ -2387,7 +2377,7 @@ remove_symbol_file_command (char *args, int from_tty)
 
   my_cleanups = make_cleanup (null_cleanup, NULL);
 
-  argv = gdb_buildargv (args);
+  gdb_argv argv (args);
 
   if (strcmp (argv[0], "-a") == 0)
     {
diff --git a/gdb/symmisc.c b/gdb/symmisc.c
index 32a5331..cfdd5d9 100644
--- a/gdb/symmisc.c
+++ b/gdb/symmisc.c
@@ -407,7 +407,6 @@ dump_symtab (struct symtab *symtab, struct ui_file *outfile)
 static void
 maintenance_print_symbols (char *args, int from_tty)
 {
-  char **argv;
   struct ui_file *outfile = gdb_stdout;
   struct cleanup *cleanups;
   char *address_arg = NULL, *source_arg = NULL, *objfile_arg = NULL;
@@ -415,8 +414,8 @@ maintenance_print_symbols (char *args, int from_tty)
 
   dont_repeat ();
 
-  argv = gdb_buildargv (args);
-  cleanups = make_cleanup_freeargv (argv);
+  gdb_argv argv (args);
+  cleanups = make_cleanup (null_cleanup, NULL);
 
   for (i = 0; argv != NULL && argv[i] != NULL; ++i)
     {
@@ -709,7 +708,6 @@ print_symbol (void *args)
 static void
 maintenance_print_msymbols (char *args, int from_tty)
 {
-  char **argv;
   struct ui_file *outfile = gdb_stdout;
   struct cleanup *cleanups;
   char *objfile_arg = NULL;
@@ -718,8 +716,8 @@ maintenance_print_msymbols (char *args, int from_tty)
 
   dont_repeat ();
 
-  argv = gdb_buildargv (args);
-  cleanups = make_cleanup_freeargv (argv);
+  gdb_argv argv (args);
+  cleanups = make_cleanup (null_cleanup, NULL);
 
   for (i = 0; argv != NULL && argv[i] != NULL; ++i)
     {
@@ -944,14 +942,11 @@ maintenance_expand_symtabs (char *args, int from_tty)
 {
   struct program_space *pspace;
   struct objfile *objfile;
-  struct cleanup *cleanups;
-  char **argv;
   char *regexp = NULL;
 
   /* We use buildargv here so that we handle spaces in the regexp
      in a way that allows adding more arguments later.  */
-  argv = gdb_buildargv (args);
-  cleanups = make_cleanup_freeargv (argv);
+  gdb_argv argv (args);
 
   if (argv != NULL)
     {
@@ -988,8 +983,6 @@ maintenance_expand_symtabs (char *args, int from_tty)
 	     ALL_DOMAIN);
 	}
     }
-
-  do_cleanups (cleanups);
 }
 
 
diff --git a/gdb/top.c b/gdb/top.c
index 6b00c6e..a4fd262 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -365,17 +365,14 @@ new_ui_command (char *args, int from_tty)
   int i;
   int res;
   int argc;
-  char **argv;
   const char *interpreter_name;
   const char *tty_name;
-  struct cleanup *success_chain;
   struct cleanup *failure_chain;
 
   dont_repeat ();
 
-  argv = gdb_buildargv (args);
-  success_chain = make_cleanup_freeargv (argv);
-  argc = countargv (argv);
+  gdb_argv argv (args);
+  argc = argv.count ();
 
   if (argc < 2)
     error (_("usage: new-ui <interpreter> <tty>"));
@@ -408,9 +405,6 @@ new_ui_command (char *args, int from_tty)
     stream[2].release ();
 
     discard_cleanups (failure_chain);
-
-    /* This restores the previous UI and frees argv.  */
-    do_cleanups (success_chain);
   }
 
   printf_unfiltered ("New UI allocated\n");
diff --git a/gdb/tracefile.c b/gdb/tracefile.c
index e208fc6..8dde605 100644
--- a/gdb/tracefile.c
+++ b/gdb/tracefile.c
@@ -318,8 +318,8 @@ tsave_command (char *args, int from_tty)
   if (args == NULL)
     error_no_arg (_("file in which to save trace data"));
 
-  argv = gdb_buildargv (args);
-  back_to = make_cleanup_freeargv (argv);
+  gdb_argv built_argv (args);
+  argv = built_argv.get ();
 
   for (; *argv; ++argv)
     {
@@ -341,7 +341,7 @@ tsave_command (char *args, int from_tty)
   else
     writer = tfile_trace_file_writer_new ();
 
-  make_cleanup (trace_file_writer_xfree, writer);
+  back_to = make_cleanup (trace_file_writer_xfree, writer);
 
   trace_save (filename, writer, target_does_save);
 
diff --git a/gdb/tracepoint.c b/gdb/tracepoint.c
index 6721e22..86acdbe 100644
--- a/gdb/tracepoint.c
+++ b/gdb/tracepoint.c
@@ -447,10 +447,6 @@ trace_variable_command (char *args, int from_tty)
 static void
 delete_trace_variable_command (char *args, int from_tty)
 {
-  int ix;
-  char **argv;
-  struct cleanup *back_to;
-
   if (args == NULL)
     {
       if (query (_("Delete all trace state variables? ")))
@@ -460,19 +456,16 @@ delete_trace_variable_command (char *args, int from_tty)
       return;
     }
 
-  argv = gdb_buildargv (args);
-  back_to = make_cleanup_freeargv (argv);
+  gdb_argv argv (args);
 
-  for (ix = 0; argv[ix] != NULL; ix++)
+  for (char *arg : argv)
     {
-      if (*argv[ix] == '$')
-	delete_trace_state_variable (argv[ix] + 1);
+      if (*arg == '$')
+	delete_trace_state_variable (arg + 1);
       else
-	warning (_("Name \"%s\" not prefixed with '$', ignoring"), argv[ix]);
+	warning (_("Name \"%s\" not prefixed with '$', ignoring"), arg);
     }
 
-  do_cleanups (back_to);
-
   dont_repeat ();
 }
 
diff --git a/gdb/utils.c b/gdb/utils.c
index 06f4168..e7e176d 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -2863,6 +2863,20 @@ ldirname (const char *filename)
   return dirname;
 }
 
+/* See utils.h.  */
+
+void
+gdb_argv::reset (const char *s)
+{
+  char **argv = buildargv (s);
+
+  if (s != NULL && argv == NULL)
+    malloc_failure (0);
+
+  freeargv (m_argv);
+  m_argv = argv;
+}
+
 /* Call libiberty's buildargv, and return the result.
    If buildargv fails due to out-of-memory, call nomem.
    Therefore, the returned value is guaranteed to be non-NULL,
diff --git a/gdb/utils.h b/gdb/utils.h
index b9bd6d9..88cab4b 100644
--- a/gdb/utils.h
+++ b/gdb/utils.h
@@ -86,6 +86,124 @@ extern int parse_pid_to_attach (const char *args);
 extern int parse_escape (struct gdbarch *, const char **);
 
 char **gdb_buildargv (const char *);
+
+/* A wrapper for an array of char* that was allocated in the way that
+   'buildargv' does, and should be freed with 'freeargv'.  */
+
+class gdb_argv
+{
+public:
+
+  /* A constructor that initializes to NULL.  */
+
+  gdb_argv ()
+    : m_argv (NULL)
+  {
+  }
+
+  /* A constructor that calls buildargv on STR.  STR may be NULL, in
+     which case this object is initialized with a NULL array.  If
+     buildargv fails due to out-of-memory, call malloc_failure.
+     Therefore, the value is guaranteed to be non-NULL, unless the
+     parameter itself is NULL.  */
+
+  explicit gdb_argv (const char *str)
+    : m_argv (NULL)
+  {
+    reset (str);
+  }
+
+  /* A constructor that takes ownership of an existing array.  */
+
+  explicit gdb_argv (char **array)
+    : m_argv (array)
+  {
+  }
+
+  gdb_argv (const gdb_argv &) = delete;
+  gdb_argv &operator= (const gdb_argv &) = delete;
+
+  ~gdb_argv ()
+  {
+    freeargv (m_argv);
+  }
+
+  /* Call buildargv on STR, storing the result in this object.  Any
+     previous state is freed.  STR may be NULL, in which case this
+     object is reset with a NULL array.  If buildargv fails due to
+     out-of-memory, call malloc_failure.  Therefore, the value is
+     guaranteed to be non-NULL, unless the parameter itself is
+     NULL.  */
+
+  void reset (const char *str);
+
+  /* Return the underlying array.  */
+
+  char **get ()
+  {
+    return m_argv;
+  }
+
+  /* Return the underlying array, transferring ownership to the
+     caller.  */
+
+  char **release ()
+  {
+    char **result = m_argv;
+    m_argv = NULL;
+    return result;
+  }
+
+  /* Return the number of items in the array.  */
+
+  int count () const
+  {
+    return countargv (m_argv);
+  }
+
+  /* Index into the array.  */
+
+  char *operator[] (int arg)
+  {
+    gdb_assert (m_argv != NULL);
+    return m_argv[arg];
+  }
+
+  /* The iterator type.  */
+
+  typedef char **iterator;
+
+  /* Return an iterator pointing to the start of the array.  */
+
+  iterator begin ()
+  {
+    return m_argv;
+  }
+
+  /* Return an iterator pointing to the end of the array.  */
+
+  iterator end ()
+  {
+    return m_argv + count ();
+  }
+
+  bool operator!= (nullptr_t)
+  {
+    return m_argv != NULL;
+  }
+
+  bool operator== (nullptr_t)
+  {
+    return m_argv == NULL;
+  }
+
+private:
+
+  /* The wrapped array.  */
+
+  char **m_argv;
+};
+
 
 /* Cleanup utilities.  */