jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

krzysztofzablocki

expr -- (void)printf("[%s, %s]\n",(char *) object_getClassName(*(long*)($esp+4)), (char *) *(long *)($esp+8) )

hujunfeng

What's the difference between UUID, GUID and UDID?

• UUID (Universally Unique Identifier): A sequence of 128 bits that can guarantee uniqueness across space and time, defined by [RFC 4122][rfc4122].

• GUID (Globally Unique Identifier): Microsoft's implementation of the UUID specification; often used interchangeably with UUID.

• UDID _(Unique Device Identifier)): A sequence of 40 hexadecimal characters that uniquely identify an iOS device (the device's Social Security Number, if you will). This value can be retrieved through iTunes, or found using UIDevice -uniqueIdentifier. Derived from hardware details like MAC address.

Is UDID deprecated?

gdavis

ACTION
AD_HOC_CODE_SIGNING_ALLOWED
ALTERNATE_GROUP
ALTERNATE_MODE
ALTERNATE_OWNER
ALWAYS_SEARCH_USER_PATHS
ALWAYS_USE_SEPARATE_HEADERMAPS
APPLE_INTERNAL_DEVELOPER_DIR
APPLE_INTERNAL_DIR
APPLE_INTERNAL_DOCUMENTATION_DIR

chriseidhof

\lstdefinelanguage{swift}
{
  morekeywords={
    func,if,then,else,for,in,while,do,switch,case,default,where,break,continue,fallthrough,return,
    typealias,struct,class,enum,protocol,var,func,let,get,set,willSet,didSet,inout,init,deinit,extension,
    subscript,prefix,operator,infix,postfix,precedence,associativity,left,right,none,convenience,dynamic,
    final,lazy,mutating,nonmutating,optional,override,required,static,unowned,safe,weak,internal,
    private,public,is,as,self,unsafe,dynamicType,true,false,nil,Type,Protocol,
  },
  morecomment=[l]{//}, % l is for line comment

syshen

######################
# Options
######################

REVEAL_ARCHIVE_IN_FINDER=false

FRAMEWORK_NAME="${PROJECT_NAME}"

SIMULATOR_LIBRARY_PATH="${BUILD_DIR}/${CONFIGURATION}-iphonesimulator/${FRAMEWORK_NAME}.framework"

praeclarum

//
//  ArrayDiff.swift
//
//  Created by Frank A. Krueger on 6/30/15.
//  Copyright © 2015 Krueger Systems, Inc. All rights reserved.
//  License: MIT http://opensource.org/licenses/MIT
//

import Foundation

alanzeino

LLDB Debugging Cheat Sheet

Commands

LLDB Commands

LLDB comes with a great set of commands for powerful debugging.

help

Your starting point for anything. Type help to get a list of all commands, plus any user installed ones. Type 'help for more information on a command. Type help to get help for a specific option in a command too.

ikonst

#!/bin/sh
set -e

# Converts a Quicktime movie to a GIF aniamtion.
# Useful for screen recordings.
# Preliminary step with palette required to make it look good
# without dithering artifacts.

FPS=10
PALETTE=$(mktemp).png

khanlou

import Foundation

final class SafeSyncQueue {

    struct QueueIdentity {
        let label: String
    }

    let queue: DispatchQueue