GROFF_TRACE(7) GROFF_TRACE(7)
NAME
groff_trace - groff macro package trace.tmac
SYNOPSIS
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.
DESCRIPTION
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 diag-nostic diagnostic
nostic 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 com-mand command
mand 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 messages.
EXAMPLES
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 example.
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.
FILES
The trace macros are kept in the file trace.tmac located in the tmac directory; see groff_tmac(5) for
details.
ENVIRONMENT
$GROFF_TMAC_PATH
A colon-separated list of additional tmac directories in which to search for macro files; see
groff_tmac(5) for details.
AUTHOR
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 <http://www.gnu.org/copyleft/fdl.html.
This document is part of groff, the GNU roff distribution. It was written by
Bernd Warken <bwarken@mayn.de>.
SEE ALSO
groff(1)
An overview of the groff system.
troff(1)
For details on option -m.
groffer(1)
A viewer program for all kinds of roff documents.
groff_tmac(5)
A general description of groff macro packages.
groff(7)
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.
Groff Version 1.19.2 18 July 2003 GROFF_TRACE(7)
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