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man pages section 7: Standards, Environments, Macros, Character Sets, and Miscellany

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Updated: Wednesday, July 27, 2022

groff_trace (7)


groff_trace - groff macro package trace.tmac


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


Miscellaneous Information Manual                                GROFF_TRACE(7)

       groff_trace - groff macro package trace.tmac

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

       The  trace  macro package of groff(1) can be a valuable tool for debug-
       ging documents written in the roff formatting language.  A  call  stack
       trace  is  protocolled on standard error, this is, 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 com-
       mand 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 command line option -r trace-full=1 is given (or if this register is
       set in the document), number and string register  assignments  together
       with some other requests are traced also.

       If  some other macro package should be traced as well it must be speci-
       fied 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 stan-
       dard input.  As we are  only  interested  in  the  diagnostic  messages
       (standard error) on the terminal, the normal formatted output (standard
       output) is redirected to 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 test_macro
              *** 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 child
              *** .de parent
              *** 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.

       Because trace.tmac wraps the .de request (and its cousins), macro argu-
       ments are expanded one level more.  This causes problems if an argument
       contains four backslashes or more to prevent too early expansion of the
       backslash.  For example, this macro call

              .foo \\\\n[bar]

       normally passes `\\n[bar]' to macro `.foo', but with the redefined  .de
       request it passes `\n[bar]' instead.

       The  solution  to  this problem is to use groff's \E escape which is an
       escape character not interpreted in copy mode, for example

              .foo \En[bar]

       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.

       See attributes(7) for descriptions of the following attributes:

       |Availability   | text/groff       |
       |Stability      | Uncommitted      |

              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.

       Copyright (C) 2002-2014 Free Software Foundation, Inc.

       This file is part of groff, the GNU roff type-setting system.

       Permission  is  granted to copy, distribute and/or modify this document
       under the terms of the GNU Free Documentation License, Version  1.3  or
       any  later  version published by the Free Software Foundation; with the
       Invariant Sections being this .ig-section and AUTHOR,  with  no  Front-
       Cover Texts, and with no Back-Cover Texts.

       A  copy  of the Free Documentation License is included as a file called
       FDL in the main directory of the groff source package.

       Written by Bernd Warken <groff-bernd.warken-72@web.de>.

       Source code for open source software components in Oracle  Solaris  can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-

       This    software    was    built    from    source     available     at
       https://github.com/oracle/solaris-userland.    The  original  community
       source                was                downloaded                from

       Further information about this software can be found on the open source
       community website at https://www.gnu.org/software/groff.

Groff Version 1.22.3            4 November 2014                 GROFF_TRACE(7)