Camel Rest Area

Compare iPhone Price

Posted on 2017-10-13

Please following the core code or clone the project from Github

def getPrice(country):
    url = "https://www.apple.com/" + country + "/shop/buy-iphone/iphone-8/"
    resp = request.urlopen(url)
    html_data = resp.read().decode('utf-8')
    soup = bs(html_data.lower(), 'html.parser')
    url_data = soup.script.string
    for item in json.loads(url_data)['offers']:
        sku = item['sku']
        if (re.search('mq6', sku)):
            price = item['price']
            pricecurrency = item['pricecurrency']
            print(sku + ": " + str(price) + " " + pricecurrency)

Recommended Visual Studio Code Extensions

Posted on 2017-10-02

What is `Visual Studio Code` aka `VSCode`

Microsoft clone Sublime project to create a new editor. It’s different with Visual Studio. VSCode is more simple, quickly and friendly. I love this project that supports many extensions for improving the experience.

I don’t introduce how to install VSCode and how to search extensions. I think it’s a easy job. I focus on how to use extensions and how to set up.

`C/C++`

I’m a embedded system engineer and telecommunication engineer. I often use C/C++ to implement the ideas and do my jobs. VSCode also recommend this extension.

`C++ Intellisense`

I use this extensions to find the referneces in my code. It’s a powerful feature like as Source Insight.

How to set up the environment. Just install global.

$ brew install global
How to use it. Please go to your project folder and type gtags

$ gtags
Find references

`Astyle`

Must be formated your code all the time and talk your team to use the same code style.

How to set up the environment. Just install install

$ brew install astyle
You can try the following settings for formatting the code.

$ astyle –style=google -s2 -S -N -L -m0 -M40 –add-braces –delete-empty-lines –convert-tabs –suffix=none

`Git History` and `Git Blame`

To use Git to manage the project that is the best way. You can try to install Git History and Git Blame that provide a simple way to check out your commits.

`vscode-icons`

Nothing important. It provide VSCode to display the icons for each file.

`CMake`

To use CMake to compile your project that is more powerful than Makefile.

How to use Git bisect

Posted on 2017-10-02

Git is a complex management system but powerful. Sometimes you need to figure out some weird problems. You can read the paragraph if you want to find someone broke the code.

Using `bisect` to find the compiled error commit

You already knowed which committed was good and which committed was bad. That’s try to find out what the problem. Just type

$ git bisect start
$ git bisect good <good commit id>
$ git bisect bad <bad commit id>

Git will help you to checkout each commit for testing the code when you mark the commit is bad

$ make
gcc ... Error 1
$ git bisect bad

How to use script to find the compiled error

You can write the following script to help you find out the bad commit. If compiled error that the script response 1 and vice versa.

#!/bin/sh

make clean >/dev/null
make &> file.txt >/dev/null
if [[ `grep Error file.txt` ]]; then
  exit 1
else
  exit 0
fi
rm file.txt

How to use script for `bisect`

Use git bisect run for running the script.

$ git bisect start
$ git bisect good <good commit id>
$ git bisect bad <bad commit id>
$ git bisect run ./find_compile_error.sh

Now you can send the mail to someone, notice him/her to fix the problem.
If you want to exit bisect, just type

$ git bisect reset

Use jekyll to create a blog on github

Posted on 2017-09-24

Install jekyll firstly https://pcjustin.github.io/2017/09/17/install-jekyll-on-mac.html

And following the simple way to create your own blog.

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3

$ jekyll new my-awesome-site
$ cd my-awesome-site
$ jekyll s

How to create a post

create a folder names ‘_posts’
add a post names ‘2017-01-01-my-first-blog.md’
use markdown to write something

---
layout: post
title: my first blog
---

This is my first post.

How to modify blog name and something else

modify _config.yml

This file include many features what you want to.

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3

title: My blog
author: My name
email: my@email.com

Create more information

Modify about.md

---
layout: page
title: About
permalink: /about/
---

This is my information.

How to publish the post to github

create a blog in github https://pages.github.com/

publish the post to github

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$ git add _posts
$ git commit -m "my first blog"
$ git push -u origin master

How to add page views

Many ways to support visitors counter and post views in your blog. Please following the simple way to support it.

create the own layout

Copy the ‘_includes’ and ‘_layouts’ to your blog. In Mac, you can use the command to find out the folder.

1	$ open $(bundle show minima)

add external javascript in head.html

1	<script async src="//dn-lbstatics.qbox.me/busuanzi/2.3/busuanzi.pure.mini.js"></script>

<div class="footer-col footer-col-3">
    <p>{{ site.description | escape }}</p>
    <span id="busuanzi_container_site_pv">
          Visitors: <span id="busuanzi_value_site_pv"></span>
    </span>
</div>

add page views in post.html

<p class="post-meta">
• <span id="busuanzi_container_page_pv">
    View: <span id="busuanzi_value_page_pv">
</span></span></p>

Something else

Now you can create the own blog or copy others into your blog.

If you want to learn how to use markdown for writing your post, you can following the link.

And you can find out more templates for improving the layout.

How to use arm-none-eabi-gcc on CMake

Posted on 2017-09-24

To follow this instructions that solve the compiled problem.

To create a cmake file named ‘cross_compile.cmake’

set(CMAKE_SYSTEM_NAME Generic)
set(CMAKE_SYSTEM_PROCESSOR arm)
set(CMAKE_C_COMPILER ${TOOLCHAIN_DIR}/bin/arm-none-eabi-gcc)
set(CMAKE_EXE_LINKER_FLAGS "--specs=nosys.specs" CACHE INTERNAL "")

Following the command for cross compiling

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3

$ mkdir build
$ cd build
$ cmake -DCMAKE_TOOLCHAIN_FILE=../cross_compile.cmake ..

Remember that don’t forget the ‘CMakeLists.txt’.
That’s all. Hope it will be worked in your project. I will introduce CMake for next topic.

How to reduce the memory size of the code

Posted on 2017-09-24

You don’t care memory size in PC but it is small in the embedded system. This post shows a couple of simple ways to reduce the wasted memory in your code.

Use dynamic allocation
Don’t use global variable
Refactoring your code
How to calculate memory size

Use dynamic allocation

Static variables use many memory sizes until the program exits. You should use dynamic allocation if you don’t use as the same as memory each time or you don’t use the variables again.

Don’t use global variable

Compare the memory size with global variable and local variable. global variable use more memory size because the variable alives when the program begins.

global.c

int size[10000];
int main()
{
    memset(size, 0x0, sizeof(size));
    return 0;
}

$ size global
__TEXT	__DATA
4096	40960

local.c

int main()
{
    int size[10000];
    memset(size, 0x0, sizeof(size));
    return 0;
}
$ size local
__TEXT	__DATA
4096	4096

Refactoring your code

You should refactor your code many times. You can find out many code that can use as the same as the function and variable.

How to calculate memory size

Let’s talking more details about stack and heap and something else.

What is stack
What is heap
What is .bss and .data and .text

stack [1]

The stack area contains the program stack, a LIFO structure, typically located in the higher parts of memory. When call function, local variable will put into stack until the function exits. If you write a recursive function, it use many stacks.

Please following the code that use 40 bytes until function ‘run1’ exits.

void run2() {
    u16 num[10];
}
void run1() {
    u16 num[10];
    run2();
}

heap [1]

The heap area commonly begins at the end of the .bss and .data segments and grows to larger addresses from there. The heap area is managed by malloc, calloc, realloc, and free, which may use the brk and sbrk system calls to adjust its size

Please following the code that use 10 bytes until free the variable ‘str’.

void run3() {
    void *str;
    str = malloc(sizeof(u8) * 10);
    //...
    free(str);
}

What is .bss and .data

.bss [1]

The BSS segment, also known as uninitialized data, is usually adjacent to the data segment. The BSS segment contains all global variables and static variables that are initialized to zero or do not have explicit initialization in source code.

.data [1]

The .data segment contains any global or static variables which have a pre-defined value and can be modified.

.text [1]

The code segment, also known as a text segment or simply as text, is where a portion of an object file or the corresponding section of the program’s virtual address space that contains executable instructions is stored and is generally read-only and fixed size.

GCC defines

Posted on 2017-09-24

I was writing Makefile and CMakefile and I was thinking how many defines in GCC and Clang. Please following the command to get the GCC defines and it’s compatible with Clang.

1	$ gcc -E -dM - </dev/null

#define OBJC_NEW_PROPERTIES 1
#define _LP64 1
#define __APPLE_CC__ 6000
#define __APPLE__ 1
#define __ATOMIC_ACQUIRE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_CONSUME 1
#define __ATOMIC_RELAXED 0
#define __ATOMIC_RELEASE 3
#define __ATOMIC_SEQ_CST 5
#define __BIGGEST_ALIGNMENT__ 16
#define __BLOCKS__ 1
#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
#define __CHAR16_TYPE__ unsigned short
#define __CHAR32_TYPE__ unsigned int
#define __CHAR_BIT__ 8
#define __CONSTANT_CFSTRINGS__ 1
#define __DBL_DECIMAL_DIG__ 17
#define __DBL_DENORM_MIN__ 4.9406564584124654e-324
#define __DBL_DIG__ 15
#define __DBL_EPSILON__ 2.2204460492503131e-16
#define __DBL_HAS_DENORM__ 1
#define __DBL_HAS_INFINITY__ 1
#define __DBL_HAS_QUIET_NAN__ 1
#define __DBL_MANT_DIG__ 53
#define __DBL_MAX_10_EXP__ 308
#define __DBL_MAX_EXP__ 1024
#define __DBL_MAX__ 1.7976931348623157e+308
#define __DBL_MIN_10_EXP__ (-307)
#define __DBL_MIN_EXP__ (-1021)
#define __DBL_MIN__ 2.2250738585072014e-308
#define __DECIMAL_DIG__ __LDBL_DECIMAL_DIG__
#define __DYNAMIC__ 1
#define __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ 101200
#define __FINITE_MATH_ONLY__ 0
#define __FLT_DECIMAL_DIG__ 9
#define __FLT_DENORM_MIN__ 1.40129846e-45F
#define __FLT_DIG__ 6
#define __FLT_EPSILON__ 1.19209290e-7F
#define __FLT_EVAL_METHOD__ 0
#define __FLT_HAS_DENORM__ 1
#define __FLT_HAS_INFINITY__ 1
#define __FLT_HAS_QUIET_NAN__ 1
#define __FLT_MANT_DIG__ 24
#define __FLT_MAX_10_EXP__ 38
#define __FLT_MAX_EXP__ 128
#define __FLT_MAX__ 3.40282347e+38F
#define __FLT_MIN_10_EXP__ (-37)
#define __FLT_MIN_EXP__ (-125)
#define __FLT_MIN__ 1.17549435e-38F
#define __FLT_RADIX__ 2
#define __FXSR__ 1
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __GCC_ATOMIC_LLONG_LOCK_FREE 2
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_16 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GNUC_MINOR__ 2
#define __GNUC_PATCHLEVEL__ 1
#define __GNUC_STDC_INLINE__ 1
#define __GNUC__ 4
#define __GXX_ABI_VERSION 1002
#define __INT16_C_SUFFIX__
#define __INT16_FMTd__ "hd"
#define __INT16_FMTi__ "hi"
#define __INT16_MAX__ 32767
#define __INT16_TYPE__ short
#define __INT32_C_SUFFIX__
#define __INT32_FMTd__ "d"
#define __INT32_FMTi__ "i"
#define __INT32_MAX__ 2147483647
#define __INT32_TYPE__ int
#define __INT64_C_SUFFIX__ LL
#define __INT64_FMTd__ "lld"
#define __INT64_FMTi__ "lli"
#define __INT64_MAX__ 9223372036854775807LL
#define __INT64_TYPE__ long long int
#define __INT8_C_SUFFIX__
#define __INT8_FMTd__ "hhd"
#define __INT8_FMTi__ "hhi"
#define __INT8_MAX__ 127
#define __INT8_TYPE__ signed char
#define __INTMAX_C_SUFFIX__ L
#define __INTMAX_FMTd__ "ld"
#define __INTMAX_FMTi__ "li"
#define __INTMAX_MAX__ 9223372036854775807L
#define __INTMAX_TYPE__ long int
#define __INTMAX_WIDTH__ 64
#define __INTPTR_FMTd__ "ld"
#define __INTPTR_FMTi__ "li"
#define __INTPTR_MAX__ 9223372036854775807L
#define __INTPTR_TYPE__ long int
#define __INTPTR_WIDTH__ 64
#define __INT_FAST16_FMTd__ "hd"
#define __INT_FAST16_FMTi__ "hi"
#define __INT_FAST16_MAX__ 32767
#define __INT_FAST16_TYPE__ short
#define __INT_FAST32_FMTd__ "d"
#define __INT_FAST32_FMTi__ "i"
#define __INT_FAST32_MAX__ 2147483647
#define __INT_FAST32_TYPE__ int
#define __INT_FAST64_FMTd__ "ld"
#define __INT_FAST64_FMTi__ "li"
#define __INT_FAST64_MAX__ 9223372036854775807L
#define __INT_FAST64_TYPE__ long int
#define __INT_FAST8_FMTd__ "hhd"
#define __INT_FAST8_FMTi__ "hhi"
#define __INT_FAST8_MAX__ 127
#define __INT_FAST8_TYPE__ signed char
#define __INT_LEAST16_FMTd__ "hd"
#define __INT_LEAST16_FMTi__ "hi"
#define __INT_LEAST16_MAX__ 32767
#define __INT_LEAST16_TYPE__ short
#define __INT_LEAST32_FMTd__ "d"
#define __INT_LEAST32_FMTi__ "i"
#define __INT_LEAST32_MAX__ 2147483647
#define __INT_LEAST32_TYPE__ int
#define __INT_LEAST64_FMTd__ "ld"
#define __INT_LEAST64_FMTi__ "li"
#define __INT_LEAST64_MAX__ 9223372036854775807L
#define __INT_LEAST64_TYPE__ long int
#define __INT_LEAST8_FMTd__ "hhd"
#define __INT_LEAST8_FMTi__ "hhi"
#define __INT_LEAST8_MAX__ 127
#define __INT_LEAST8_TYPE__ signed char
#define __INT_MAX__ 2147483647
#define __LDBL_DECIMAL_DIG__ 21
#define __LDBL_DENORM_MIN__ 3.64519953188247460253e-4951L
#define __LDBL_DIG__ 18
#define __LDBL_EPSILON__ 1.08420217248550443401e-19L
#define __LDBL_HAS_DENORM__ 1
#define __LDBL_HAS_INFINITY__ 1
#define __LDBL_HAS_QUIET_NAN__ 1
#define __LDBL_MANT_DIG__ 64
#define __LDBL_MAX_10_EXP__ 4932
#define __LDBL_MAX_EXP__ 16384
#define __LDBL_MAX__ 1.18973149535723176502e+4932L
#define __LDBL_MIN_10_EXP__ (-4931)
#define __LDBL_MIN_EXP__ (-16381)
#define __LDBL_MIN__ 3.36210314311209350626e-4932L
#define __LITTLE_ENDIAN__ 1
#define __LONG_LONG_MAX__ 9223372036854775807LL
#define __LONG_MAX__ 9223372036854775807L
#define __LP64__ 1
#define __MACH__ 1
#define __MMX__ 1
#define __NO_INLINE__ 1
#define __NO_MATH_INLINES 1
#define __OBJC_BOOL_IS_BOOL 0
#define __ORDER_BIG_ENDIAN__ 4321
#define __ORDER_LITTLE_ENDIAN__ 1234
#define __ORDER_PDP_ENDIAN__ 3412
#define __PIC__ 2
#define __POINTER_WIDTH__ 64
#define __PRAGMA_REDEFINE_EXTNAME 1
#define __PTRDIFF_FMTd__ "ld"
#define __PTRDIFF_FMTi__ "li"
#define __PTRDIFF_MAX__ 9223372036854775807L
#define __PTRDIFF_TYPE__ long int
#define __PTRDIFF_WIDTH__ 64
#define __REGISTER_PREFIX__
#define __SCHAR_MAX__ 127
#define __SHRT_MAX__ 32767
#define __SIG_ATOMIC_MAX__ 2147483647
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIZEOF_DOUBLE__ 8
#define __SIZEOF_FLOAT__ 4
#define __SIZEOF_INT128__ 16
#define __SIZEOF_INT__ 4
#define __SIZEOF_LONG_DOUBLE__ 16
#define __SIZEOF_LONG_LONG__ 8
#define __SIZEOF_LONG__ 8
#define __SIZEOF_POINTER__ 8
#define __SIZEOF_PTRDIFF_T__ 8
#define __SIZEOF_SHORT__ 2
#define __SIZEOF_SIZE_T__ 8
#define __SIZEOF_WCHAR_T__ 4
#define __SIZEOF_WINT_T__ 4
#define __SIZE_FMTX__ "lX"
#define __SIZE_FMTo__ "lo"
#define __SIZE_FMTu__ "lu"
#define __SIZE_FMTx__ "lx"
#define __SIZE_MAX__ 18446744073709551615UL
#define __SIZE_TYPE__ long unsigned int
#define __SIZE_WIDTH__ 64
#define __SSE2_MATH__ 1
#define __SSE2__ 1
#define __SSE3__ 1
#define __SSE4_1__ 1
#define __SSE_MATH__ 1
#define __SSE__ 1
#define __SSP__ 1
#define __SSSE3__ 1
#define __STDC_HOSTED__ 1
#define __STDC_UTF_16__ 1
#define __STDC_UTF_32__ 1
#define __STDC_VERSION__ 201112L
#define __STDC__ 1
#define __UINT16_C_SUFFIX__
#define __UINT16_FMTX__ "hX"
#define __UINT16_FMTo__ "ho"
#define __UINT16_FMTu__ "hu"
#define __UINT16_FMTx__ "hx"
#define __UINT16_MAX__ 65535
#define __UINT16_TYPE__ unsigned short
#define __UINT32_C_SUFFIX__ U
#define __UINT32_FMTX__ "X"
#define __UINT32_FMTo__ "o"
#define __UINT32_FMTu__ "u"
#define __UINT32_FMTx__ "x"
#define __UINT32_MAX__ 4294967295U
#define __UINT32_TYPE__ unsigned int
#define __UINT64_C_SUFFIX__ ULL
#define __UINT64_FMTX__ "llX"
#define __UINT64_FMTo__ "llo"
#define __UINT64_FMTu__ "llu"
#define __UINT64_FMTx__ "llx"
#define __UINT64_MAX__ 18446744073709551615ULL
#define __UINT64_TYPE__ long long unsigned int
#define __UINT8_C_SUFFIX__
#define __UINT8_FMTX__ "hhX"
#define __UINT8_FMTo__ "hho"
#define __UINT8_FMTu__ "hhu"
#define __UINT8_FMTx__ "hhx"
#define __UINT8_MAX__ 255
#define __UINT8_TYPE__ unsigned char
#define __UINTMAX_C_SUFFIX__ UL
#define __UINTMAX_FMTX__ "lX"
#define __UINTMAX_FMTo__ "lo"
#define __UINTMAX_FMTu__ "lu"
#define __UINTMAX_FMTx__ "lx"
#define __UINTMAX_MAX__ 18446744073709551615UL
#define __UINTMAX_TYPE__ long unsigned int
#define __UINTMAX_WIDTH__ 64
#define __UINTPTR_FMTX__ "lX"
#define __UINTPTR_FMTo__ "lo"
#define __UINTPTR_FMTu__ "lu"
#define __UINTPTR_FMTx__ "lx"
#define __UINTPTR_MAX__ 18446744073709551615UL
#define __UINTPTR_TYPE__ long unsigned int
#define __UINTPTR_WIDTH__ 64
#define __UINT_FAST16_FMTX__ "hX"
#define __UINT_FAST16_FMTo__ "ho"
#define __UINT_FAST16_FMTu__ "hu"
#define __UINT_FAST16_FMTx__ "hx"
#define __UINT_FAST16_MAX__ 65535
#define __UINT_FAST16_TYPE__ unsigned short
#define __UINT_FAST32_FMTX__ "X"
#define __UINT_FAST32_FMTo__ "o"
#define __UINT_FAST32_FMTu__ "u"
#define __UINT_FAST32_FMTx__ "x"
#define __UINT_FAST32_MAX__ 4294967295U
#define __UINT_FAST32_TYPE__ unsigned int
#define __UINT_FAST64_FMTX__ "lX"
#define __UINT_FAST64_FMTo__ "lo"
#define __UINT_FAST64_FMTu__ "lu"
#define __UINT_FAST64_FMTx__ "lx"
#define __UINT_FAST64_MAX__ 18446744073709551615UL
#define __UINT_FAST64_TYPE__ long unsigned int
#define __UINT_FAST8_FMTX__ "hhX"
#define __UINT_FAST8_FMTo__ "hho"
#define __UINT_FAST8_FMTu__ "hhu"
#define __UINT_FAST8_FMTx__ "hhx"
#define __UINT_FAST8_MAX__ 255
#define __UINT_FAST8_TYPE__ unsigned char
#define __UINT_LEAST16_FMTX__ "hX"
#define __UINT_LEAST16_FMTo__ "ho"
#define __UINT_LEAST16_FMTu__ "hu"
#define __UINT_LEAST16_FMTx__ "hx"
#define __UINT_LEAST16_MAX__ 65535
#define __UINT_LEAST16_TYPE__ unsigned short
#define __UINT_LEAST32_FMTX__ "X"
#define __UINT_LEAST32_FMTo__ "o"
#define __UINT_LEAST32_FMTu__ "u"
#define __UINT_LEAST32_FMTx__ "x"
#define __UINT_LEAST32_MAX__ 4294967295U
#define __UINT_LEAST32_TYPE__ unsigned int
#define __UINT_LEAST64_FMTX__ "lX"
#define __UINT_LEAST64_FMTo__ "lo"
#define __UINT_LEAST64_FMTu__ "lu"
#define __UINT_LEAST64_FMTx__ "lx"
#define __UINT_LEAST64_MAX__ 18446744073709551615UL
#define __UINT_LEAST64_TYPE__ long unsigned int
#define __UINT_LEAST8_FMTX__ "hhX"
#define __UINT_LEAST8_FMTo__ "hho"
#define __UINT_LEAST8_FMTu__ "hhu"
#define __UINT_LEAST8_FMTx__ "hhx"
#define __UINT_LEAST8_MAX__ 255
#define __UINT_LEAST8_TYPE__ unsigned char
#define __USER_LABEL_PREFIX__ _
#define __VERSION__ "4.2.1 Compatible Apple LLVM 8.1.0 (clang-802.0.42)"
#define __WCHAR_MAX__ 2147483647
#define __WCHAR_TYPE__ int
#define __WCHAR_WIDTH__ 32
#define __WINT_TYPE__ int
#define __WINT_WIDTH__ 32
#define __amd64 1
#define __amd64__ 1
#define __apple_build_version__ 8020042
#define __block __attribute__((__blocks__(byref)))
#define __clang__ 1
#define __clang_major__ 8
#define __clang_minor__ 1
#define __clang_patchlevel__ 0
#define __clang_version__ "8.1.0 (clang-802.0.42)"
#define __core2 1
#define __core2__ 1
#define __llvm__ 1
#define __nonnull _Nonnull
#define __null_unspecified _Null_unspecified
#define __nullable _Nullable
#define __pic__ 2
#define __strong
#define __tune_core2__ 1
#define __unsafe_unretained
#define __weak __attribute__((objc_gc(weak)))
#define __x86_64 1
#define __x86_64__ 1

First post

Posted on 2017-09-24

It’s my fist post. The blog is talking technical, news, blah blah blah, something else.

這是我第一篇文章。此blog將會說些技術、新聞和一些有得沒有的事情。

Install Mosh

Posted on 2017-09-24

What is Mosh
How to install mosh server
How to login server over mosh
How to add private key for auto-login

What is Mosh

Mosh is a replacement for SSH. Mosh runs the mosh-server remotely and connects to it over UDP.

How to install mosh server

Mac

1	brew install mobile-shell

Windows
Mosh haven’t native mosh client in Windows. You can install Chrome extensions or install mosh on cygwin.

Download Chrome Extensions
Install mosh on cygwin
1
C:\setup.exe -q mobile-shell
How to login over mosh
Use Chrome extensions to login the server

![](/images/mosh-chrome.jpg)

Create a private key for accessing the system. Recommend to set up passphrase for protecting private key.

1	$ ssh-keygen -t rsa

Copy public key to authorized_keys

$ cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
$ chmod 400 ~/.ssh/authorized_keys
Optional
$ rm ~/.ssh/id_rsa.pub

Copy private key into mosh client.

1	$ cat ~/.ssh/id_rsa

Click ‘Add ssh key’ to insert private key.

![](/images/add-ssh-key.jpg)

Git basic

Posted on 2017-09-24

How to start

Learn how to clone others repository
Learn how to create your own repository
Learn how to commit your code to git server
Learn how to development
Learn how to code review
Learn more things

Clone others repository

To download from a HTTPS url

1	$ git clone https://github.com/pcjustin/pcjustin.github.io.git

To download from a SSH url

1 2	$ git clone git@github.com:pcjustin/pcjustin.github.io.git

Create your own repository

To create a empty repository

1	$ git init new-repository

To add your code for commiting

1	$ git add main.c

To commit your code to local

1	$ git commit -m "initial commit"

Commit your code to git server

To set up remote server

1	$ git remote add origin https://github.com/pcjustin/pcjustin.github.io.git

To push your code

1	$ git push -u origin master

Using Git to development

Please following the Golden rules:

Don’t develop in master branch.
Don’t develop in develepment branch.
Create a sandbox or something branch for developemnt.
Combine multipe commits when merging back to development branch.
Rebase is good
That’s hack it.

Create a branch

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3

$ git checkout dev
$ git checkout -b sandbox/pcjustin/add_hello_world
$ git push -u origin sandbox/pcjustin/add_hello_world

Rebase your multiple commits

HEAD~3 means how many commits do you want to combine

1	$ git rebase -i HEAD~3

Merge your code into developement branch

1
2
3

$ git checkout dev
$ git merge sandbox/pcjustin/add_hello_world
$ git push -u origin dev

Update your code from development branch

Sometimes you need to solve some conflicts.

1 2	$ git checkout sandbox/pcjustin/add_hello_world $ git rebase dev

Code review

How to code review

Many services support Git for code review. I prefer Gerrit to code reivew that is stable version.

1
2
3

$ git checkout dev
$ git merge sandbox/pcjustin/add_hello_world
$ git push origin HEAD:refs/for/dev

How to modify my review when modify the code

1
2
3

$ git add main.c
$ git commit --amend
$ git push origin HEAD:refs/for/dev

How to update my review when merge conflicts

You need to solve local conflicts.

$ git checkout dev
$ git pull origin dev
$ git rebase origin/dev
$ git push origin HEAD:refs/for/dev

Download code review from Gerrit

1	$ git-review -d <change id>

One more thing

How to clean the remote repositories

1	$ git remote prune origin

To be continued

What is Visual Studio Code aka VSCode

C/C++

C++ Intellisense

Astyle

Git History and Git Blame

vscode-icons

CMake

Using bisect to find the compiled error commit

How to use script to find the compiled error

How to use script for bisect

How to create a post

How to modify blog name and something else

modify _config.yml

Create more information

Modify about.md

How to publish the post to github

How to add page views

create the own layout

add external javascript in head.html

add visitors counter in footer.html

add page views in post.html

Something else

Use dynamic allocation

Don’t use global variable

Refactoring your code

How to calculate memory size

stack [1]

heap [1]

What is .bss and .data

.bss [1]

.data [1]

.text [1]

What is Mosh

How to install mosh server

How to login over mosh

How to add private key for auto-login

How to start

Clone others repository

To download from a HTTPS url

To download from a SSH url

Create your own repository

To create a empty repository

To add your code for commiting

To commit your code to local

Commit your code to git server

To set up remote server

To push your code

Using Git to development

Create a branch

Rebase your multiple commits

Merge your code into developement branch

Update your code from development branch

Code review

How to code review

How to modify my review when modify the code

How to update my review when merge conflicts

Download code review from Gerrit

One more thing

How to clean the remote repositories

What is `Visual Studio Code` aka `VSCode`

`C/C++`

`C++ Intellisense`

`Astyle`

`Git History` and `Git Blame`

`vscode-icons`

`CMake`

Using `bisect` to find the compiled error commit

How to use script for `bisect`