Intel XENIX 286 Programmers Guide (86) - Tenox.tc

XENIX Programming make: Program Maintainer
make also has built-in pseudo-target names that modify its operation. The pseudotarget
name ".IGNO RE" causes make to ignore errors during execution of commands,
allowing make to continue after an error. This is the same as the -i option. (make also
ignores errors for a given command if the command string begins with a hyphen (-).)
The pseudo-target name ".DEFAULT" defines the commands to be executed when no
built-in rule or user-defined dependency line exists for the given target. You may give
any number of commands with this name. If ".DEFAULT" is not used and an undefined
target is given, make prints a message and stops.
The pseudo-target name ".PRECIOUS" prevents dependents of the current target from
being deleted when make is terminated using the INTERRUPT or QUIT key, and the
pseudo-target name ".SILENT" has the same effect as the -s option.
Using Macros
An important feature of a makefile is that it can contain macros. A macro is a short
name that represents a file name or command option. The macros can be defined when
you invoke make or in the makefile itself.
A macro definition is a line containing an equal sign not preceded by a colon or a tab.
The name (string of letters and digits) to the left of the equal sign (trailing blanks and
tabs are stripped) is assigned the string of characters following the equal sign (leading
blanks and tabs are stripped). The following are valid macro definitions:
2 = xyz
abc = -II -ly
LIBES =
The last definition assigns "LIBES" the null string. A macro that is never explicitly
defined has the null string as its value.
A macro is invoked by preceding the name by a dollar sign; macro names longer than one
character must be placed in parentheses. The name of the macro is either the single
character after the dollar sign or a name inside parentheses. The following are valid
macro invocations:
$(CFLAGS)
$2
$(xy)
$Z
$(Z)
The last two invocations are identical.
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