This is the mail archive of the mailing list for the GDB project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH 3/4] GDBServer: introduce --server-stderr command line option

On 03/21/2015 05:26 AM, Eli Zaretskii wrote:
From: Cleber Rosa <>
Date: Fri, 20 Mar 2015 23:34:24 -0300

This command line option will redirect all of the gdbserver's own
output (always sent to stderr) to a separate file. This feature
makes it possible to distinguish between the inferior process stderr
and gdbserver's own stderr.
+@cindex @option{--server-stderr}, @code{gdbserver} option
+The @option{--server-stderr} option tells @code{gdbserver} that any content
+that it would normally generate itself to its own @code{stderr} should be
+redirected to another file. This is useful if you want to keep the
+inferior @code{stderr} separate from the one generated by @code{gdbserver}.
Note how the text description of the rationale for the change you
posted to explain it to us is much more useful than the technical
description in the manual.  Why not say in the manual what you told

 From the user POV, the fact that gdbserver uses stderr for its own
output is an implementation detail that is almost unimportant.  (It
could be important for redirection purposes, but the command-line
option you introduce eliminates the need to redirect in most cases,
right?)  What _is_ important is that gdbserver's own output will be
redirected to that file, and that important information gets lost in
the confusing "it would normally generate itself to its own 'stderr'",
which leaves unanswered the question what part of gdbserver's output
is "normally" excluded from that.

Your comments make a lot of sense. Indeed using "normally" introduces unnecessary doubt and confusion. Also, the user friendlier text in the commit message won't reach users. Good catches!

For this reason, I suggest to name the option "--server-output".


BTW, to keep a more obvious correlation between variable name (server_stderr) and command line option (now --server-output), I'm going to rename the former unless someone feels strongly against it.

And I think we want a NEWS entry for this change.


+@item --server-stderr
+Instruct @code{gdbserver} to redirect its own @code{stderr} to another
The option requires an argument, so the argument should be mentioned
with the option and referenced in the text that describes it.

Sure, I also feel an example could help. How do you feel about this:

@cindex @option{--server-output}, @code{gdbserver} option
The @option{--server-output=path} option tells @code{gdbserver} to send
all its output to a file given by @var{path}. This can be useful, for instance, if you need to collect the server output and/or the inferior output, but want
to keep them separate:

$ gdbserver --server-output=server.log :2222 testprog >test.out 2>test.err
@end smallexample

+static int
+set_server_stderr (char *path)
+  FILE *tmp;
+  tmp = fopen (path, "w");
+  if (tmp == NULL)
+    {
+      fprintf (stderr,
+	       "Could not open server stderr file '%s': %s\n",
+	       path, strerror(errno));
+      return -1;
+    }
+  server_stderr = tmp;
+  return 0;
  monitor_show_help (void)
@@ -3017,6 +3036,7 @@ gdbserver_usage (FILE *stream)
  	   "                            none\n"
  	   "                            timestamp\n"
  	   "  --remote-debug        Enable remote protocol debugging output.\n"
+	   "  --server-stderr=PATH  Redirect server's STDERR to file at PATH.\n"
  	   "  --version             Display version information and exit.\n"
  	   "  --wrapper WRAPPER --  Run WRAPPER to start new programs.\n"
  	   "  --once                Exit after the first connection has "
@@ -3186,7 +3206,13 @@ captured_main (int argc, char *argv[])
while (*next_arg != NULL && **next_arg == '-')
-      if (strcmp (*next_arg, "--version") == 0)
+      if (strncmp (*next_arg, "--server-stderr=",
+		   sizeof ("--server-stderr=") - 1) == 0)
+	{
+	  char *path = *next_arg + (sizeof ("--server-stderr=") - 1);
+	  set_server_stderr (path);
+	}
+      else if (strcmp (*next_arg, "--version") == 0)
AFAIK, GNU Coding Standards frown on using "path" for anything that is
not PATH-style list of directories.  So please use "file" or "file
name" here.

I could not find a mention on the GNU Coding Standards manual itself, but yeah, it may be (informally?) frowned upon as it's indeed confusing.


Thank you for the comments and very valid points!

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]