구차니의 잡동사니 모음

아랫방향 검색

/검색어 

n

윗방향 검색

?검색어

N

대소문자 구분

:set noci

대소문자 비구분

:set ci

치환

:%s/FROM/TO

치환(질문)

:%s/FROM/TO/c

정확한 치환

:%s/\<FROM\>/TO

치환 대소문자 비구분

:%s/FROM/TO/i

치환 파일전체

:%s/FROM/TO/g

[링크 : http://mwultong.blogspot.com/2006/09/vim-vi-gvim-find-and-replace.html]

+

2017.04.10

[링크 : https://kldp.org/node/74138]

test.c:3:1: error: 'main' must return 'int'

clang은 int main() 아니면 배쨰는 중 -_-

음.. 코드가 허접한거라..

시간은 큰 의미가 없지만.. 아무튼 빌드가 아니라 --analyze만 해서는

$ time gcc -o gcc.o test.c

test.c: In function ‘main’:

test.c:7:2: warning: incompatible implicit declaration of built-in function ‘free’ [enabled by default]

real    0m0.611s

user    0m0.510s

sys     0m0.070s

$ time clang -o gcc.o test.c

test.c:7:2: warning: implicit declaration of function 'free' is invalid in C99

      [-Wimplicit-function-declaration]

        free(p);

        ^

1 warning generated.

real    0m0.728s

user    0m0.560s

sys     0m0.110s

$ time clang -o gcc.o test.c --analyze

test.c:7:2: warning: Function call argument is an uninitialized value

        free(p);

        ^    ~

1 warning generated.

real    0m0.325s

user    0m0.220s

sys     0m0.080s

clang이 요즘 뜨는건지.. 한번 해보려는데.. 흐음...

일단 귀차니즘으로.. (-_-) 라즈베리 파이에 ㅋㅋ

$ scan-build clang++ a.cpp

scan-build: 'clang' executable not found in '/usr/share/clang/scan-build/bin'.

scan-build: Using 'clang' from path: /usr/bin/clang

scan-build: Removing directory '/tmp/scan-build-2015-08-03-1' because it contains no reports.

[링크 : http://web.cs.ucla.edu/~tianyi.zhang/tutorial.html]

$ clang --analyze a.cpp

[링크 : http://kthan.tistory.com/158]

yocto proejct - poky 다운로드

meta-raspberrypi layer 다운로드

환경변수 및 라즈베리 파이 빌드할 경로 생성

라즈베리 파이 빌드를 위한 환경 설정 1

라즈베리 파이 빌드를 위한 환경 설정 2

빌드를 위한 패키지 설치(라즈비안에서 한 120메가 다운로드 / 500메가 용량 필요)

빌드 시작

리부팅후 환경변수 재설정

끄응.. 왜 안되지? 라즈베리에서 라즈베리를 빌드하려고 해서 그런가? ㅋㅋㅋ

pi@raspberrypi ~/src/yoctoProject/raspberryPiBuild $ bitbake core-sato-image

WARNING: Host distribution "Raspbian-GNU-Linux-7" has not been validated with this version of the build system; you may possibly experience unexpected failures. It is recommended that you use a tested distribution.

ERROR: Unable to determine endianness for architecture 'armv6l' | ETA:  --:--:--

ERROR: Please add your architecture to siteinfo.bbclass

ERROR: Failed to parse recipe: /home/pi/src/yoctoProject/meta/recipes-core/coreutils/coreutils_8.24.bb

Summary: There was 1 WARNING message shown.

Summary: There were 3 ERROR messages shown, returning a non-zero exit code.

---

pi@raspberrypi ~/src/yoctoProject $ ls -al

합계 92

drwxr-xr-x 12 pi pi  4096  7월 30 06:33 .

drwxr-xr-x 10 pi pi  4096  7월 30 06:29 ..

drwxr-xr-x  8 pi pi  4096  7월 30 06:33 .git

-rw-r--r--  1 pi pi   346  7월 30 06:32 .gitignore

-rw-r--r--  1 pi pi    66  7월 30 06:32 .templateconf

-rw-r--r--  1 pi pi   515  7월 30 06:32 LICENSE

-rw-r--r--  1 pi pi  2458  7월 30 06:32 README

-rw-r--r--  1 pi pi 19318  7월 30 06:32 README.hardware

drwxr-xr-x  6 pi pi  4096  7월 30 06:32 bitbake

drwxr-xr-x 13 pi pi  4096  7월 30 06:32 documentation

drwxr-xr-x 21 pi pi  4096  7월 30 06:32 meta

drwxr-xr-x 13 pi pi  4096  7월 30 06:33 meta-raspberrypi

drwxr-xr-x  5 pi pi  4096  7월 30 06:32 meta-selftest

drwxr-xr-x  7 pi pi  4096  7월 30 06:32 meta-skeleton

drwxr-xr-x  5 pi pi  4096  7월 30 06:32 meta-yocto

drwxr-xr-x  8 pi pi  4096  7월 30 06:32 meta-yocto-bsp

-rwxr-xr-x  1 pi pi  2002  7월 30 06:32 oe-init-build-env

-rwxr-xr-x  1 pi pi  2432  7월 30 06:32 oe-init-build-env-memres

drwxr-xr-x  8 pi pi  4096  7월 30 06:32 scripts

pi@raspberrypi ~/src $ du -h yoctoProject/

178M    yoctoProject/

[링크 : http://ric96.blogspot.in/2014/09/yocto-for-raspberry-pi-build-guide.html]

-c -o gch를 통해서 gcc precompiled header를 생성이 가능하다.

물론 gch가 생성되면 원래 헤더파일이 사라져도 문제없이 컴파일 된다.

확장자 gch로 확인하기 때문에 다른 확장자로 변경시 gch 헤더를 찾지 못한다.

-c가 좀더 간편한듯.

-x c++-hedaer

-x c-header는 너무 길어 -_-

-c는 찾는거 포기 -_-

췟 이건 안되네 -_-

결론 -c -o .gch로 하자

2015/07/29 - [프로그램 사용/gcc] - gcc에서 precompiled header 사용하기

한번 시도는 해봐야겠다.

g++ -Wall -fexceptions -H  -g     -c main.cpp -o obj/Debug/main.o

! /usr/local/include/boost/xpressive/xpressive.hpp.gch

main.cpp

. /usr/include/c++/4.4/iostream

.. /usr/include/c++/4.4/x86_64-linux-gnu/bits/c++config.h

.. /usr/include/c++/4.4/ostream

.. /usr/include/c++/4.4/istream

main.cpp

The ! means that the compiler was able to use the precompiled header. An x means it was not able to use it. Using the appropriate compiler flags is crucial. I took off the -H and ran some speed tests. The precompiled header had an improvement from 14 seconds to 11 seconds. Not bad but not great.

Note: Here's the link to the example: http://www.boost.org/doc/libs/1_43_0/doc/html/xpressive/user_s_guide.html#boost_xpressive.user_s_guide.examples I couldn't get it to work in the post.

[링크 : http://stackoverflow.com/questions/58841/precompiled-headers-with-gcc]

Caution: There are a few known situations where GCC will crash when trying to use a precompiled header. If you have trouble with a precompiled header, you should remove the precompiled header and compile without it.

To create a precompiled header file, simply compile it as you would any other file, if necessary using the -x option to make the driver treat it as a C or C++ header file.

Each of the following options must be the same when building and using the precompiled header:

          -fexceptions -funit-at-a-time

[링크 : https://gcc.gnu.org/onlinedocs/gcc-4.0.0/gcc/Precompiled-Headers.html]

아래는 cpp 의 경우,

g++ -x c++-header stdafx.h -o stdafx.h.gch

아래는 c 의 경우,

gcc -x c-header stdafx.h -o stdafx.h.gch

[링크 : https://kldp.org/node/22714]

Precompiled headers are supported in GCC (3.4 and newer).

[링크 : http://softwareji.tistory.com/65]

일단은 yocto 프로젝트의 코어인 poky를 받고(빌드 환경 구성 + 커널 등등?)

하드웨어 의존적인 metadata layer를 다운로드 받는다(meta-raspberrypi)

1.     Clone the Yocto Project Git repo

2.     Get the meta-raspberrypi layer

3.     Setup the build environment

4.     Configure the build

5.     Next up, we need to add the meta-rasperrypi layer we cloned earlier to the file conf/bblayers.conf.

6.     Build a minimal distribution

[링크 : http://ric96.blogspot.in/2014/09/yocto-for-raspberry-pi-build-guide.html]

[링크 : http://git.yoctoproject.org/cgit/cgit.cgi/meta-raspberrypi/about/]

Poky is a reference system of the Yocto Project - a collection of Yocto Project tools and metadata that serves as a set of working examples. To use the Yocto Project tools, you can download Poky and use it to bootstrap your own distribution.

Poky is the platform-independent, cross-compiling integration layer that utilizes OpenEmbedded Core. It provides the mechanism to build and combine thousands of distributed open source projects together to form a fully customizable, complete, coherent Linux software stack.

[링크 : https://www.yoctoproject.org/tools-resources/projects/poky]

[링크 : http://git.yoctoproject.org/]

[링크 : http://www.yoctoproject.org/docs/1.8/ref-manual/ref-manual.html]

lighttpd 설정관련해서 epoll이 먼지 조사...

읽어봐도 모르겠다.. -_-

현재 epoll은 realtime signal과 함께 가장 빠른 입출력 처리 방식 중 하나로 알려져 있습니다.

[링크 : http://www.joinc.co.kr/modules/moniwiki/wiki.php/Site/Network_Programing/AdvancedComm/epoll24]

리얼타임 시그날 (RealTime Sinal)의 대안으로 제안

[링크 : http://www.xevious7.com/52]

epoll은 '한 대의 서버에서 아주많은 동시접속자를 처리하기 위한 수단'이다.

M$ window$ 환경의 개발자라면 이미 iocp 라는 훌륭한 도구가 있고 ?FreeBSD라면 kqueue라는 도구가 있다.

[링크 : http://biscuit.cafe24.com/moniwiki/wiki.php/epoll]

Event Handlers

--------------

The first one is the Event Handler which takes care of notifying the server

that one of the connections is ready to send or receive. As you can see,

every OS has at least the select() call which has some limitations.

============ ========== ===============

OS           Method     Config Value

============ ========== ===============

all          select     select

Unix         poll       poll

Linux 2.4+   rt-signals linux-rtsig

Linux 2.6+   epoll      linux-sysepoll

Solaris      /dev/poll  solaris-devpoll

FreeBSD, ... kqueue     freebsd-kqueue

NetBSD       kqueue     kqueue

============ ========== ===============

For more information on this topic take a look at http://www.kegel.com/c10k.html

[링크 : http://redmine.lighttpd.net/projects/lighttpd/wiki/Docs_Performance/16]

[링크 : http://redmine.lighttpd.net/projects/1/wiki/Server_event-handlerDetails]

epoll

This is the recommended edge-triggered poll replacement for the 2.6 Linux kernel.

On 11 July 2001, Davide Libenzi proposed an alternative to realtime signals; his patch provides what he now calls /dev/epoll www.xmailserver.org/linux-patches/nio-improve.html. This is just like the realtime signal readiness notification, but it coalesces redundant events, and has a more efficient scheme for bulk event retrieval.

Epoll was merged into the 2.5 kernel tree as of 2.5.46 after its interface was changed from a special file in /dev to a system call, sys_epoll. A patch for the older version of epoll is available for the 2.4 kernel.

There was a lengthy debate about unifying epoll, aio, and other event sources on the linux-kernel mailing list around Halloween 2002. It may yet happen, but Davide is concentrating on firming up epoll in general first.

[링크 : http://www.kegel.com/c10k.html]

웹 개발시 많이 쓰는 녀석으로

개발환경을 동일하게 만들고 배포하는데 쓰인다고 한다.

[링크 : https://www.freebsd.org/doc/handbook/jails.html]

[링크 : https://en.wikipedia.org/wiki/FreeBSD_jail]

[링크 : https://www.docker.com/]

[링크 : http://pyrasis.com/Docker/Docker-HOWTO]

[링크 : http://pyrasis.com/docker.html]

+

2013/01/13 - [프로그램 사용/gcc] - gcc 64bit 확장