The make program allows you to use macros, which are similar to variables. Macros are defined in a Makefile as = pairs. For example:
MACROS= -me
PSROFF= groff -Tps
DITROFF= groff -Tdvi
CFLAGS= -O -systype bsd43
LIBS = "-lncurses -lm -lsdl"
MYFACE = ":*)"
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Before issuing any command in a target rule set there are certain special macros predefined.
So, for example, we could use a rule
hello: main.cpp hello.cpp factorial.cpp
$(CC) $(CFLAGS) $? $(LDFLAGS) -o $@
alternatively:
hello: main.cpp hello.cpp factorial.cpp
$(CC) $(CFLAGS) $@.cpp $(LDFLAGS) -o $@
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In this example $@ represents hello and $? or $@.cpp will pickup all the changed source files.
There are two more special macros used in the implicit rules. They are
Common implicit rule is for the construction of .o (object) files out of .cpp (source files).
.o.cpp:
$(CC) $(CFLAGS) -c $<
alternatively
.o.cpp:
$(CC) $(CFLAGS) -c $*.c
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NOTE: You will get more detail about Makefile Rules in another section.
There are lots of default macros (type "make -p" to print out the defaults). Most are pretty obvious from the rules in which they are used:
These predefined variables ie. macros used in implicit rules fall into two classes: those that are names of programs (like CC) and those that contain arguments for the programs (like CFLAGS).
Here is a table of some of the more common variables used as names of programs in built-in rules: makefiles.
AR | Archive-maintaining program; default `ar'. |
AS | Program for compiling assembly files; default `as'.
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CC | Program for compiling C programs; default `cc'.
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CO | Program for checking out files from RCS; default `co'.
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CXX | Program for compiling C++ programs; default `g++'.
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CPP | Program for running the C preprocessor, with results to standard output; default `$(CC) -E'.
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FC | Program for compiling or preprocessing Fortran and Ratfor programs; default `f77'.
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GET | Program for extracting a file from SCCS; default `get'.
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LEX | Program to use to turn Lex grammars into source code; default `lex'.
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YACC | Program to use to turn Yacc grammars into source code; default `yacc'.
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LINT | Program to use to run lint on source code; default `lint'.
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M2C | Program to use to compile Modula-2 source code; default `m2c'.
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PC | Program for compiling Pascal programs; default `pc'.
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MAKEINFO | Program to convert a Texinfo source file into an Info file; default `makeinfo'.
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TEX | Program to make TeX dvi files from TeX source; default `tex'.
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TEXI2DVI | Program to make TeX dvi files from Texinfo source; default `texi2dvi'.
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WEAVE | Program to translate Web into TeX; default `weave'.
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CWEAVE | Program to translate C Web into TeX; default `cweave'.
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TANGLE | Program to translate Web into Pascal; default `tangle'.
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CTANGLE | Program to translate C Web into C; default `ctangle'.
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RM | Command to remove a file; default `rm -f'.
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Here is a table of variables whose values are additional arguments for the programs above. The default values for all of these is the empty string, unless otherwise noted.
ARFLAGS | Flags to give the archive-maintaining program; default `rv'.
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ASFLAGS | Extra flags to give to the assembler (when explicitly invoked on a `.s' or `.S' file).
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CFLAGS | Extra flags to give to the C compiler.
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CXXFLAGS | Extra flags to give to the C compiler.
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COFLAGS | Extra flags to give to the RCS co program.
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CPPFLAGS | Extra flags to give to the C preprocessor and programs that use it (the C and Fortran compilers).
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FFLAGS | Extra flags to give to the Fortran compiler.
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GFLAGS | Extra flags to give to the SCCS get program.
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LDFLAGS | Extra flags to give to compilers when they are supposed to invoke the linker, `ld'.
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LFLAGS | Extra flags to give to Lex.
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YFLAGS | Extra flags to give to Yacc.
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PFLAGS | Extra flags to give to the Pascal compiler.
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RFLAGS | Extra flags to give to the Fortran compiler for Ratfor programs.
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LINTFLAGS | Extra flags to give to lint.
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NOTE: You can cancel all variables used by implicit rules with the `-R' or `--no-builtin-variables' option.
You can also define macros at the command line such as
make CPP = /home/courses/cop4530/spring02
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