Notes: make 命令 & makefile

makefile syntax

dependencies (相依性項目)

one target (目標項目)
some source code files
(target), (semicolon), (space or tab), ....., (source code files), (space or tab), .....
e.g. all: myapp myapp.l

rules (法則)

the rules illustrate how to generate a target
(tab)
the rules muse be on the same line

comment (註解)

macro (巨集)

define the macro => MACRONAME = value
access the macro => $(MACRONAME), ${MACRONAME}

make will ignore the error
e.g. -mkdir
e.g. -rm -r

make will not output the executed command on standard output

#這是makefile的格式(註解)
[target]: [dependency] [dependency]
[TAB][rule]
[TAB][rule]
[target]: [dependency]
[TAB][rule]

make options

-k : 會讓make再遇到錯誤之時，仍然繼續執行而不會停在第一個問題點。可以利用這個選項找出發生問題的原始碼檔案。

-n : 告訴make只列出要進行的工作，而不會真正去執行它。

-f : tell the make to use the as a makefile. Otherwise, the make will use the makefile, Makefile (recommend).

-p : 要求 make 印出內建法則

-j3 : use the 3 cores

Automatic Varaiables

$@ : The name of the current target

$% : The filename element of an archive member specification

$<: first="" he="" name="" nbsp="" of="" p="" prerequisite="" the="">
$?: The names of all prerequisites that are newer than the target, separated by spaces,代表須要重建(被修改)的相依性項目

$^: The names of all prerequisites, separated by spaces. This is list has duplicated names removed.

$+: Similar to $^, except $+ includes duplicateds.. This variable was created for specific situations such as arguments to linkers where duplicated values have meaning.

$*: The stem of the target filename. A stem is typically a filename without its suffix. Current dependencies without the extension (副檔名)

define the marcro : 1) make CC=c89 2) make "CC = c89"
Use the all as the first target in makefile
all (target)
install (target)
uninstall (target)
clean (target)

GNU gcc

gcc -MM : generate a dependency list to make

Conventional Macros (common built in rules of makefiles)

typing "make −p" to print out the defaults

AR	Archive−maintaining program; default is `ar'.
AS	Program for compiling assembly files; default is `as'.
CC	Program for compiling C programs; default is `cc'.
CO	Program for checking out files from RCS; default is `co'.
CXX	Program for compiling C++ programs; default is `g++'.
CPP	Program for running the C preprocessor, with results to standard output; default is `$(CC) -E'.

ARFLAGS	Flags to give the archive-maintaining program; default is `rv'.
ASFLAGS	Extra flags to give to the assembler when explicitly invoked on a `.s' or `.S' file.
CFLAGS	Extra flags to give to the C compiler.
CXXFLAGS	Extra flags to give to the C compiler.
COFLAGS	Extra flags to give to the RCS co program.
CPPFLAGS	Extra flags to give to the C preprocessor and programs, which use it (such as C and Fortran compilers).

Conditional Directives

ifeq
ifneq
ifdef
ifndef
else
endif

e.g.

ifeq (arg1, arg2)
ifeq 'arg1' 'arg2'
ifeq "arg1" "arg2"
ifeq "arg1" 'arg2'
ifeq 'arg1' "arg2"

make 命令 & makefile