.TH tcng 1 2007-11-15 Debian TCNG
.SH NAME
tcng \- Traffic control compiler
.SH SYNOPSIS
.B tcng
[
.B -c
] [
.BI -d " ..."
] [
.B -E
] [
.BI -i " <default_interface>"
] [
.BI -l " <location_file>"
] [
.B -n
] [
.B -q
] [
.B -r
] [
.B -w
] [
.BI -W " [no]<condition>"
] [
.BI -O " [no]<option>"
] [
.BI -x " <element>:<ext_target> ..."
] [
.BI -t " [no]<target> ..."
] [
.BI -u " <var_use_file>"
] [
.BI -X " <phase>,<argument>"
] [
.I <cpp_option>
] [
.I <file>
]
.SH DESCRIPTION
The
.B tcng
language is extensively described in several formats, you can find
these files in 
.IR "/usr/share/doc/tcng" "."
This manpage describes nothing but command-line arguments.
.P
.B tcng
reads traffic control specifications in the tcng language and 
generates command or files for a number of mechanisms that are used to 
implement traffic control functionality.
.TP
.BI -c
only check validity of input, don't build a configuration. If 
requested, the location file and the variable use file are also 
generated when using -c 
.TP
.BI -d
increase debugging level
.TP
.BI -E
only run cpp, and send its output to standard output. This is useful 
for separately running files through cpp, while using the default 
includes added by tcng. 
.TP
.BI -i " <default_interface>"
interface to use if none is specified in the 
description file. See section \*(lqInterfaces revisited\*(rq for further 
details. 
.TP
.BI -l " <location_file>"
write a list of source code locations of traffic 
control elements to the specified file. See section \*(lqLocation map\*(rq for 
details. Using the special file name \*(lqstderr\*(rq sends the output to 
standard error. 
.TP
.BI -n
do not include \*(lqdefault.tc\*(rq. By default, tcng includes this file, 
which in turn includes the files described in section \*(lqInclude files\*(rq. 
This can be undesirable, e.g. if operating in a non-TCP/IP context, or 
if using a different default include file with application-specific 
definitions. In the latter case, the following options should be used:
tcng ... -n ... -Xp,--include -Xp,/<directory>/<file> ... 
.TP
.BI -O "[no]<option>"
enable or disable the specified optimization. The 
following optimizations are recognized: 
.RS
.I \*(lqcse\*(rq
common subexpression elimination 
.br
.I \*(lqne\*(rq
turn != into multiple ==s 
.br
.I \*(lqprefix\*(rq
generate prefix matches instead of bit tests 
.RE
By default, all optimizations except \*(lqcse\*(rq are turned off. 
.TP
.BI -q
quiet, produce terse output 
.TP
.BI -r
remove old queuing disciplines before adding new ones ("tc" only) 
.TP
.BI -t " [<elem:>][no]<target> ..."
enable or disable target (see section 
\*(lqTargets\*(rq). The only element currently supported is \*(lqif\*(rq. Supported 
targets are \*(lqall\*(rq, \*(lqtc\*(rq (default), \*(lqc\*(rq, and \*(lqext\*(rq. The -t options can 
be repeated to enable or disable multiple targets. 
.TP
.BI -u "<var_use_file>"
for each variable, write its name and value to the 
specified file. See section \*(lqVariable use list\*(rq for details. Using the 
special file name \*(lqstderr\*(rq sends the output to standard error. 
.TP
.BI -V
print version number and exit 
.TP
.BI -w
suppress all warnings 
.TP
.BI -W "[no]<condition>"
enable or disable issuing a warning message on the 
specified condition. The following conditions are recognized: 
.RS
.I \*(lqconstpfx\*(rq
warn if using the / (mask) operator on a constant IPv4 or 
IPv6 address, as in ip_src == 1.2.3.0/24, which should probably be 
ip_src/24 == 1.2.3.0 
.br
.I \*(lqexpensive\*(rq
generate warnings when encountering \*(lqexpensive\*(rq 
constructs in \*(lqif\*(rq classifier. A construct is considered 
\*(lqexpensive\*(rq if processing it may take tcng an unusual amount of 
time. Operations like negation, certain tests for non-equality, or 
static classification that follows metering, are \*(lqexpensive\*(rq.
.br
Because \*(lqexpensive\*(rq may be overly pessimistic, \*(lqexppostopt\*(rq should 
be used whenever possible. 
.br
.I \*(lqexperror\*(rq
turns warnings from \*(lqexpensive\*(rq or \*(lqexppostopt\*(rq into 
fatal errors. Setting \*(lqexperror\*(rq without also setting \*(lqexpensive\*(rq 
or \*(lqexppostopt\*(rq has no effect. 
.br
.I \*(lqexplicit\*(rq
warn if a class if explicitly specified for the inner 
queuing discipline of \*(lqdsmark\*(rq, \*(lqegress\*(rq, or \*(lqingress\*(rq 
.br
.I \*(lqexppostopt\*(rq
like \*(lqexpensive\*(rq, but test for \*(lqexpensive\*(rq constructs 
after trying to optimize the expression, which may eliminate some 
apparently expensive constructs. \*(lqexppostopt\*(rq can only indicate in 
which \*(lqif\*(rq classifier the expression occurred, not in which 
selector of that classifier. \*(lqexpensive\*(rq has no effect if 
\*(lqexppostopt\*(rq is set.
.br
Note that neither \*(lqexpensive\*(rq nor \*(lqexppostopt\*(rq are useful when 
using \*(lqnocombine\*(rq (see sectionbarriers). 
.br
.I \*(lqredefine\*(rq
warn if re-defining variables 
.br
.I \*(lqtruncate\*(rq
warn if truncating values, e.g. when converting a 
floating-point number to an integer 
.br
.I \*(lqunused\*(rq
report unused variables 
.br
    By default, all warnings except "explicit" and "unused" are turned off. 
.RE
.TP
.BI -x " <element>:<ext_target> ..."
register external target (see section 
\*(lqTargets\*(rq). The -x option can be repeated to register multiple external 
targets. 
.TP
.BI -X "<phase>,<argument>"
verbatim argument for specific build phase. See 
section \*(lqPhases underneath tcng\*(rq for details. 
.TP
.I "<cpp_option>"
one of the following options for the C pre-processor: 
.BI -I "<dir>"
,
.BI -D "<name>[=<value>]"
, or 
.BI -U "<name> "
.P
.B tcng
also recognizes a number of undocumented options, such as 
.B -B
and
.B -N. 
These options usually enable experimental features, like alternative 
algorithms for processing \*(lqif\*(rq expressions, and they are not recommended 
for normal use of tcng. Changes to undocumented options are mentioned in 
tcng's change log (file /usr/share/doc/tcng/CHANGES).