OV2640 1600 1200

OV7620 640 480

PAL制式摄像头：OV6620、sonyCCD、LG CCD OV5116等
NTSC制式摄像头：OV7620、OV7640等

ssh -oProxyCommand="nc -x 127.0.0.1:3128 %h %p" user@site.com

bsd-netcat has -x proxy

diskutil list

gpt

hdiutil

hdiutil burn -erase //fast erase

hdiutil burn -fullerase 

hdiutil burn iso

hdiutil burn iso -device 

hdiutil burn -list // list device

@class
@defs
@protocol @required @optional @end
@interface @public @package @protected @private @property @end
@implementation @synthesize @dynamic @end
@throw @try @catch @finally
@synchronized @autoreleasepool
@selector @encode
@compatibility_alias
@”string”

cmake . -LH //=./configure --help

cmake -DBUILD_SHARED_LIBS=NO  -D CMAKE_INSTALL_PREFIX="/usr/local" .

BUILD_SHARED_LIBS

CMAKE_INSTALL_PREFIX

export CXXFLAGS="-std=c++11 -stdlib=libc++"
export LDFLAGS="-stdlib=libc++"

link to libc++ or libstdc++

the stl function symbol in object file are different in mac with xcode 7

when use std::vector as a argument

the argument symbol is St6vectorIiSaIi linking to libstdc++

the other is St3__16vectorIiNS6_9allocatorIi

this will cause linking errors

首先从静态库中解压 .o 文件

ar -x lib.a

nm查看符号表  找到重复的函数符号名

nm a.o

c和c++的符号表不一样

0000000000000000 T __Z4testv //c++

0000000000000000 T test //c

隐藏符号 相当于加 static

ld -r a.o -unexported_symbol  __Z4testv -o c.o; rm a.o; mv c.o a.o //mac 下可使用

objcopy --localize-symbol=_Z4testv a.o
 

修改符号名称

ld -r a.o -alias __Z4testv test_c  -unexported_symbol  __Z4testv -o c.o //mac 下可使用

objcopy --redefine-sym _Z4testv=test_a a.o

如果其他 .o文件引用了这个函数 对每一个文件都要执行

判断字符串是否为整数

[[ "${str}" =~ ^-?[[:digit:]]*$ ]]  //正则表达式 不能加引号

expr match "$str" "^-\?[0-9]*$"

判断字符串 包含 123

[[ "${str}" == *"123"* ]]

获取osx下的键盘输入

NSKeyDown事件需要 申请权限

(System Preferences → Security & Privacy → Accessibility)

    NSDictionary *dict=@{(__bridge NSString *)kAXTrustedCheckOptionPrompt:@YES};
    BOOL istrue=AXIsProcessTrustedWithOptions((__bridge CFDictionaryRef)dict);
    NSLog(@"%d",istrue);

方法1 cocoa