Provided by: groff_1.18.1.1-11_i386 bug


       groff_trace - groff macro package trace.tmac


       groff -m trace [options...] [files...]

       Elements  in brackets denote optional arguments, and the ellipsis means
       that there can be any number of arguments of this kind.


       The trace macro  package  of  groff(1)  can  be  a  valuable  tool  for
       debugging  documents  written  in the roff formatting language.  A call
       stack trace is protocolled on standard error, that means, a  diagnostic
       message  is  emitted  on  entering  and  exiting of a macro call.  This
       greatly eases to track down an error in some macro.

       This tracing process is activated by  specifying  the  groff  or  troff
       command  line  option  -m  trace.   This works also with the groffer(1)
       viewer program.  A finer control can be obtained by including the macro
       file within the document by the groff macro call .mso trace.tmac.  Only
       macros that are defined after this line are traced.

       If some other macro package  should  be  traced  as  well  it  must  be
       specified after -m trace on the command line.

       The  macro  file  trace.tmac is unusual because it does not contain any
       macros to be called by a user.  Instead, the existing macro  definition
       and appending facilities are modified such that they display diagnostic


       In the following examples, a  roff  fragment  is  fed  into  groff  via
       standard  input.   As we are only interested in the diagnostic messages
       (standard error) on the terminal, the normal formatted output (standard
       output) is redirected into the nirvana device /dev/null.  The resulting
       diagnostic messages are  displayed  directly  below  the  corresponding

   Command line option
       sh# echo ’.
       >   .de test_macro
       >   ..
       >   .test_macro
       >   .test_macro some dummy arguments
       >   ’ | groff -m trace >/dev/null

       *** de trace enter: test_macro
       *** trace exit: test_macro
       *** de trace enter: test_macro "some" "dummy" "arguments"
       *** trace exit: test_macro "some" "dummy" "arguments"

       The  entry and the exit of each macro call is displayed on the terminal
       (standard output) — together with the arguments (if any).

   Nested macro calls
       sh# echo ’.
       >   .de child
       >   ..
       >   .de parent
       >   .child
       >   ..
       >   .parent
       >   ’ | groff -m trace >/dev/null

       *** de trace enter: parent
       *** de trace enter: child
       *** trace exit: child
       *** trace exit: parent

       This shows that macro calls can be nested.  This powerful  feature  can
       help to tack down quite complex call stacks.

   Activating with .mso
       sh# echo ’.
       >   .de before
       >   ..
       >   .mso trace.tmac
       >   .de after
       >   ..
       >   .before
       >   .after
       >   .before
       >   ’ | groff >/dev/null

       *** de trace enter: after
       *** trace exit: after

       Here,  the  tracing  is activated within the document, not by a command
       line option.  As tracing was not active when macro before was  defined,
       no  call  of  this  macro  is protocolled; on the other hand, the macro
       after is fully protocolled.


       The trace macros are kept in the file trace.tmac located  in  the  tmac
       directory; see groff_tmac(5) for details.


              A  colon-separated  list of additional tmac directories in which
              to search for macro files; see groff_tmac(5) for details.


       Copyright (C) 2002 Free Software Foundation, Inc.

       This document is distributed under the  terms  of  the  FDL  (GNU  Free
       Documentation  License) version 1.1 or later.  You should have received
       a copy of the FDL on your system, it is also available on-line  at  the
       GNU copyleft site 〈〉.

       This  document  is  part  of  groff, the GNU roff distribution.  It was
       written by Bernd Warken 〈〉.


              An overview of the groff system.

              For details on option -m.

              A viewer program for all kinds of roff documents.

              A general description of groff macro packages.

              A short reference for the groff formatting language.

       A complete reference for all parts of the groff system is found in  the
       groff info(1) file.