구차니의 잡동사니 모음

가장 간편(?)한 건...

그런데 이렇게 건드리는게 옳은건가...

[링크 : https://forums.xilinx.com/.../Trouble-configuring-petalinux-2013-10-bin-sh-1-pushd-not-found/td-p/399843]

SHELL 변수로 설정되지 않으면 /bin/sh가 되므로

bash에서 지원하는 popd pushd 등이 봉인..

환경 변수 등을 끌어 가지 않으므로.. 결론은 Makefile 별로 설정을 해주어야 한다.

5.3.2 Choosing the Shell

The program used as the shell is taken from the variable SHELL. If this variable is not set in your makefile, the program /bin/sh is used as the shell. The argument(s) passed to the shell are taken from the variable .SHELLFLAGS. The default value of .SHELLFLAGS is -c normally, or -ec in POSIX-conforming mode.

Unlike most variables, the variable SHELL is never set from the environment. This is because the SHELL environment variable is used to specify your personal choice of shell program for interactive use. It would be very bad for personal choices like this to affect the functioning of makefiles. See Variables from the Environment.

Furthermore, when you do set SHELL in your makefile that value is not exported in the environment to recipe lines that make invokes. Instead, the value inherited from the user’s environment, if any, is exported. You can override this behavior by explicitly exporting SHELL (see Communicating Variables to a Sub-make), forcing it to be passed in the environment to recipe lines.

[링크 : https://www.gnu.org/software/make/manual/html_node/Choosing-the-Shell.html]

    [링크 : https://www.gnu.org/software/make/manual/html_node/Variables_002fRecursion.html]

 In short, variables defined with := are expanded once, but variables defined with = are expanded whenever they are used.

[링크 : http://stackoverflow.com/.../whats-the-difference-between-and-in-makefile]

Simply expanded variables are defined by lines using ‘:=’ or ‘::=’ (see Setting Variables). Both forms are equivalent in GNU make; however only the ‘::=’ form is described by the POSIX standard (support for ‘::=’ was added to the POSIX standard in 2012, so older versions of make won’t accept this form either).

[링크 : http://www.gnu.org/software/make/manual/html_node/Flavors.html#Flavors]

https://www.gnu.org/software/make/manual/html_node/Setting.html#Setting

gcc -M을 통해서 해당 소스가 끌어와야 하는 헤더들의 목록을 얻어낼수 있다.

이걸 이용하여 역으로

make 파일에서 사용해야 하는 헤더들의 목록을 생성해 낼 수 있고

이걸 make dep나 make depend를 통해서 수행하게 된다.

생각해보니.. ifdef로 된거.. option 파일이 아닌

-D 인자를 통해서 gcc -M -Dflag 해주면... 외부에서 소스변경없이 구현이 가능해져서 더 편하려나?

[링크 : http://developinghappiness.com/?p=174]

    [링크 : http://developinghappiness.com/?page_id=222]

[링크 : http://linux.die.net/man/1/gccmakedep]