The Build program uses m4(1) to create a Makefile. The m4 directives useful for Build are listed in Section 2.4. This -f switch specifies the file to pass to m4(1) to create a customized Makefile:

% ./Build -f ../../builds/oursite.m4 
Configuration: os=SunOS, rel=4.1.4, rbase=4, rroot=4.1, arch=sun4, sfx=
Using M4=/usr/5bin/m4
Creating obj.SunOS.4.1.4.sun4 using ../devtools/OS/SunOS
Including ../../builds/oursite.m4                                   note
...

This -f switch allows you to maintain Build configurations separate from the source distribution. Whenever you use -f, a comment is automatically inserted into the resulting Makefile recording that fact. The command line, for example, will produce the following comment:

####################################################################
##### This file is automatically generated -- edit at your own risk
##### Built by you@yoursite.your.domain
##### on Sat Jan 1 05:08:38 PDT 2000 using template OS/SunOS
##### including ../../builds/oursite.m4                          note
##### in /usr/local/src/sendmail-8.12.7/src
####################################################################

Note that this build-configuration information is only preserved in the Makefile. No strings are compiled into sendmail, so it is not possible to reconstruct Build settings from the compiled binary.

If this switch is omitted, default files in the devtools/Site directory are used. See Section 2.5 for a full description of this process.

Note that the -Q and -f switches cannot be used together.