GROFF_TRACE(7) GROFF_TRACE(7)
NAME
groff_trace - groff(1,7) macro package trace.tmac
SYNOPSIS
groff(1,7) -m trace(3x,n,3x _nc_tracebits) [options...] [files...]
Elements in(1,8) brackets denote optional arguments, and the ellipsis means
that there can be any number of arguments of this kind.
DESCRIPTION
The trace(3x,n,3x _nc_tracebits) macro package of groff(1,7)(1) can be a valuable tool for debug-
ging documents written in(1,8) the roff formatting language. A call stack
trace(3x,n,3x _nc_tracebits) is protocolled on standard error(8,n), that means, a diagnostic mes-
sage is emitted on entering and exiting of a macro call. This greatly
eases to track down an error(8,n) in(1,8) some macro.
This tracing process is activated by specifying the groff(1,7) or troff com-
mand line option -m trace(3x,n,3x _nc_tracebits). This works also with the groffer(1) viewer
program. A finer control can be obtained by including the macro file(1,n)
within the document by the groff(1,7) 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 speci-
fied after -m trace(3x,n,3x _nc_tracebits) on the command line.
The macro file(1,n) 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(1,7) via stan-
dard input. As we are only interested in(1,8) the diagnostic messages
(standard error(8,n)) 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(1,3x,1 builtins) '.
> .de test_macro
> ..
> .test_macro
> .test_macro some dummy arguments
> ' | groff(1,7) -m trace(3x,n,3x _nc_tracebits) >/dev/null
*** de trace(3x,n,3x _nc_tracebits) enter: test_macro
*** trace(3x,n,3x _nc_tracebits) exit: test_macro
*** de trace(3x,n,3x _nc_tracebits) enter: test_macro "some" "dummy" "arguments"
*** trace(3x,n,3x _nc_tracebits) exit: test_macro "some" "dummy" "arguments"
The entry and the exit(3,n,1 builtins) of each macro call is displayed on the terminal
(standard output) -- together with the arguments (if(3,n) any).
Nested macro calls
sh# echo(1,3x,1 builtins) '.
> .de child
> ..
> .de parent
> .child
> ..
> .parent
> ' | groff(1,7) -m trace(3x,n,3x _nc_tracebits) >/dev/null
*** de trace(3x,n,3x _nc_tracebits) enter: parent
*** de trace(3x,n,3x _nc_tracebits) enter: child
*** trace(3x,n,3x _nc_tracebits) exit: child
*** trace(3x,n,3x _nc_tracebits) 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(1,3x,1 builtins) '.
> .de before
> ..
> .mso trace.tmac
> .de after
> ..
> .before
> .after
> .before
> ' | groff(1,7) >/dev/null
*** de trace(3x,n,3x _nc_tracebits) enter: after
*** trace(3x,n,3x _nc_tracebits) 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 af-
ter is fully protocolled.
FILES
The trace(3x,n,3x _nc_tracebits) macros are kept in(1,8) the file(1,n) trace.tmac located in(1,8) the tmac
directory; see groff_tmac(5) for details.
ENVIRONMENT
$GROFF_TMAC_PATH
A colon-separated list of additional tmac directories in(1,8) 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 Docu-
mentation License) version(1,3,5) 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(1,7), the GNU roff distribution. It was
written by Bernd Warken <bwarken@mayn.de>.
SEE ALSO
groff(1,7)(1)
An overview of the groff(1,7) 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(1,7) macro packages.
groff(1,7)(7)
A short reference for the groff(1,7) formatting language.
A complete reference for all parts of the groff(1,7) system is found in(1,8) the
groff(1,7) info(1,5,n)(1) file.
Groff Version 1.19.1 18 July 2003 GROFF_TRACE(7)