* mi/mi-cmds.c (mi_cmds): Register -list-features.

	* mi/mi-cmds.h (mi_cmd_list_features): New.
	* mi/mi-main.c (mi_cmd_list_features): New.

6 files changed, 63 insertions, 0 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 4d8e5b0..c70570d 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2007-09-16  Vladimir Prus  <vladimir@codesourcery.com>
+
+	* mi/mi-cmds.c (mi_cmds): Register -list-features.
+	* mi/mi-cmds.h (mi_cmd_list_features): New.
+	* mi/mi-main.c (mi_cmd_list_features): New.
+	
 2007-09-11  Joel Brobecker  <brobecker@adacore.com>
 
 	GDB 6.7 branch created (branch timestamp: 2007-09-07 14:00 UTC)
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 6be80d6..67f74b9 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,8 @@
+2007-09-19  Vladimir Prus  <vladimir@codesourcery.com>
+
+	* gdb.texinfo (Miscellaneous gdb/mi Commands):
+	Document -list-features.
+	
 2007-09-15  Eli Zaretskii  <eliz@gnu.org>
 
 	* gdb.texinfo (Output): Spell out which features of C's printf are
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 9a74369..4378e0c 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -21277,6 +21277,37 @@ default shows this information when you start an interactive session.
 (gdb)
 @end smallexample
 
+@subheading The @code{-list-features} Command
+@findex -list-features
+
+Returns a list of particular features of the MI protocol that
+this version of gdb implements.  A feature can be a command,
+or a new field in an output of some command, or even an
+important bugfix.  While a frontend can sometimes detect presence
+of a feature at runtime, it is easier to perform detection at debugger
+startup. 
+
+The command returns a list of strings, with each string naming an
+available feature.  Each returned string is just a name, it does not
+have any internal structure.  The list of possible feature names 
+is given below.
+
+Example output:
+
+@smallexample
+(gdb) -list-features
+^done,result=["feature1","feature2"]
+@end smallexample
+
+The current list of features is:
+
+@itemize @minus
+@item
+@samp{frozen-varobjs}---indicates presence of the
+@code{-var-set-frozen} command, as well as possible presense of the
+@code{frozen} field in the output of @code{-varobj-create}.
+@end itemize
+
 @subheading The @code{-interpreter-exec} Command
 @findex -interpreter-exec
 
diff --git a/gdb/mi/mi-cmds.c b/gdb/mi/mi-cmds.c
index 48ba208..5bd8725 100644
--- a/gdb/mi/mi-cmds.c
+++ b/gdb/mi/mi-cmds.c
@@ -88,6 +88,7 @@ struct mi_cmd mi_cmds[] =
   { "inferior-tty-set", { NULL, 0 }, NULL, mi_cmd_inferior_tty_set},
   { "inferior-tty-show", { NULL, 0 }, NULL, mi_cmd_inferior_tty_show},
   { "interpreter-exec", { NULL, 0 }, 0, mi_cmd_interpreter_exec},
+  { "list-features", { NULL, 0 }, 0, mi_cmd_list_features},
   { "overlay-auto", { NULL, 0 }, NULL, NULL },
   { "overlay-list-mapping-state", { NULL, 0 }, NULL, NULL },
   { "overlay-list-overlays", { NULL, 0 }, NULL, NULL },
diff --git a/gdb/mi/mi-cmds.h b/gdb/mi/mi-cmds.h
index 7b3eb0e..9888c85 100644
--- a/gdb/mi/mi-cmds.h
+++ b/gdb/mi/mi-cmds.h
@@ -91,6 +91,7 @@ extern mi_cmd_argv_ftype mi_cmd_gdb_exit;
 extern mi_cmd_argv_ftype mi_cmd_inferior_tty_set;
 extern mi_cmd_argv_ftype mi_cmd_inferior_tty_show;
 extern mi_cmd_argv_ftype mi_cmd_interpreter_exec;
+extern mi_cmd_argv_ftype mi_cmd_list_features;
 extern mi_cmd_argv_ftype mi_cmd_stack_info_depth;
 extern mi_cmd_argv_ftype mi_cmd_stack_info_frame;
 extern mi_cmd_argv_ftype mi_cmd_stack_list_args;
diff --git a/gdb/mi/mi-main.c b/gdb/mi/mi-main.c
index 0c4b904..93e28bf 100644
--- a/gdb/mi/mi-main.c
+++ b/gdb/mi/mi-main.c
@@ -1075,6 +1075,25 @@ mi_cmd_enable_timings (char *command, char **argv, int argc)
   return MI_CMD_ERROR;
 }
 
+enum mi_cmd_result
+mi_cmd_list_features (char *command, char **argv, int argc)
+{
+  if (argc == 0)
+    {
+      struct cleanup *cleanup = NULL;
+      cleanup = make_cleanup_ui_out_list_begin_end (uiout, "features");      
+
+      ui_out_field_string (uiout, NULL, "frozen-varobjs");
+      
+      do_cleanups (cleanup);
+
+      return MI_CMD_DONE;
+    }
+
+  error ("-list-features should be passed no arguments");
+  return MI_CMD_ERROR;
+}
+ 
 /* Execute a command within a safe environment.
    Return <0 for error; >=0 for ok.