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Previous: 31.7 Categories of MacrosChapter 31
Defined Macros
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31.8 Macros with the m4 Technique

The various features of the m4 technique use uppercase single-character macro names. The complete list of them is shown in Table 31.5. Some of these are defined by using the appropriate define m4 command (see below). Others are predefined for you by the m4 technique. See the appropriate section reference for a full description of how to use each macro.

Table 31.5: Macros Reserved with the m4 Technique
$BSection 31.10.5, $BThe BITNET relay
$CSection 31.10.9, $CThe hostname of the DECnet relay
$ESection 31.10.13, $EX.400 relay (unused)
$FSection 31.10.15, $FFAX relay
$HSection 31.10.18, $HThe mail hub
$LSection 31.10.23, $LUnknown Local User relay
$MSection 31.10.25, $MWho we are masquerading as
$RSection 31.10.32, $RThe relay for unqualified names (deprecated)
$SSection 31.10.34, $SThe Smart Host
$USection 31.10.37, $UThe UUCP name to override $k
$VSection 31.10.39, $VThe UUCP relay (for class $=V)
$WSection 31.10.41, $WThe UUCP relay (for class $=W)
$XSection 31.10.43, $XThe UUCP relay (for class $=X)
$YSection 31.10.45, $YThe UUCP relay for unclassified hosts
$ZSection 31.10.47, $ZThe version of this m4 configuration

A few m4 macros can be defined by using the m4 define command. For example, here is how you define the BITNET relay with the BITNET_RELAY keyword:

define(`BITNET_RELAY', `host.domain')dnl

See Table 31.6 for a list of those m4 macros that can be defined. The leftmost column in that table shows the keyword to use.

Table 31.6: Macros Declared with Special m4 Names
m4 nameMacroDescription
BITNET_RELAY$BSection 31.10.5The BITNET relay
confCF_VERSION$ZSection 31.10.47The version of this m4 configuration
confDOMAIN_NAME$jSection 31.10.20Official canonical name
confMAILER_NAME$nSection 31.10.26Error message sender
FAX_RELAY$FSection 31.10.15FAX relay
LUSER_RELAY$LSection 31.10.23Local user relay
MAIL_HUB$HSection 31.10.18The mail hub

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