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

XENIX Programm ing
.s Assembler source file
.y Yacc-C source grammar
.yr Yacc-Ratfor source grammar
.1 Lex source grammar
make: Program Maintainer
For example, if the file x.o is needed and there is an x.c in the description or directory,
x.c is compiled. If there is also an x.l, that grammar would be run through lex before
compiling the result.
The built-in rules are designed to reduce the size of your makefiles. They provide the
rules for creating common files from typical dependents. Reconsider the example given
in the section "Creating a Makefile." In this example, the program prog depended on
three object files, x.o, y.o, and z.o. These files in turn depended on the C language
source files x.c, y.c, and z.c. The files x.c and y.c also depended on the include file
defs. In the original example each dependency and corresponding command sequence
was explicitly given. Many of these dependency lines were unnecessary, since the builtin
rules could have been used instead. The following is all that is needed to show the
relationships between these files:
prog: x.o y.o z.o
cc x.o y.o z.o -o prog
x.o y.o: defs
In this makefile, prog depends on three object files, and an explicit com mand is given
showing how to update prog. However, the second line merely shows that two object
files depend on the include file defs. No explicit command sequence is given on how to
update these files if necessary. Instead, make uses the built-in rules to locate the
desired C source files, compile these files, and create the necessary object files.
Changing the Built-In Rules
You can change the built-in rules by redefining the macros used in these lines or by
redefining the commands associated with the rules. You can display a complete list of
the built-in rules and the macros used in the rules by typing
make -fp - 2 >ldev/null