16.2 The null.mc FileNow we will create a file called null.mc , which, when later processed, will create a client.cf -style configuration file. The null.mc fill will be very small, containing only these three lines:
include(`../m4/cf.m4') OSTYPE(`sunos4.1') FEATURE(`nullclient',`mail.us.edu') These three lines do everything that the preceding 11 chapters did and more. We discuss them individually, then show how to process the file. 16.2.1 includeNaturally, a configuration is not simply plucked from thin air. Instead the master prototype configuration needs to be read and processed with the following command: [1]
include(`../m4/cf.m4')
Note that the expression inside the parentheses begins with a reverse apostrophe
and ends with a forward one. These opposing half quotes are used by
m4
(1) to prevent a test from being interpreted as a macro.
The expression 16.2.2 OSTYPEA number of values in the configuration file will differ from operating system to operating system. The location of the queue directory, for example, is /var/spool/mqueue for IRIX 5.x but /usr/spool/mqueue for BSD 4.3 Unix. To declare the proper value for your operating system, look in the ../ostype directory:
%
Pick the operating system closest to yours. For
SunOS 4.1.4 systems, for example, choose
Whichever you choose, include support for it by stripping the
sunos4.1.m4 Remember to surround the result in a reverse and forward apostrophe pair. 16.2.3 FEATUREThe last line in our null.mc file provides the magic incantation of a client.cf -style file:
FEATURE(`nullclient',`mail.us.edu')
Two arguments inside the parentheses, separated by a comma, are
required. The first argument, |
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