The attached lldb command pblock command lets you peek inside an Objective-C block. It tries to tell you where to find the source code for the block, and the values captured by the block when it was created.
Consider this example program:
#import <Foundation/Foundation.h>
@interface Foo: NSObject
@end
@implementation Foo
The dynamic wallpaper in MacOS Mojave is a single 114 MB .heic file that seems to contain 16 embedded images.
It also contains the following binary plist data in its metadata under the key "Solar". It's an array of 16 items, each with four keys:
i (integer). This seems to be the image index.o (integer). This is always 1 or 0. Stephen Radford thinks it indicates dark mode (0) vs. light mode (1).a (decimal). I’m pretty sure this is the angle of the sun over the horizon. 0º = sunset/sunrise. 90º = sun directly overhead. Negative values = sun below horizon.z (decimal). This seems to be the cardinal position of the sun relative to the camera. 0º = sun is directly in front of the camera. 90º = sun is directly to the right of the camera. 180º = sun is directly behind the camera.
| # /etc/nsmb.conf - macOS 11.3 - 2021-04-29 | |
| #------------------------------------------------------------------------------ | |
| # SMB configuration for macOS 11.3 <-> Synology | |
| #------------------------------------------------------------------------------ | |
| # Additional information: | |
| # ----------------------- | |
| # https://support.apple.com/de-de/HT211927 | |
| # https://support.apple.com/en-us/HT208209 | |
| # https://apple.stackexchange.com/questions/309016/smb-share-deadlocks-since-high-sierra | |
| # https://photographylife.com/afp-vs-nfs-vs-smb-performance |
The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).
My take-aways are:
You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.
Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse
rebase vs merge).rebase vs merge)reset vs checkout vs revert)git rev-parse)pull vs fetch)stash vs branch)reset vs checkout vs revert)
| # The trick is to link the DeviceSupport folder from the beta to the stable version. | |
| # sudo needed if you run the Mac App Store version. Always download the dmg instead... you'll thank me later :) | |
| # Support iOS 15 devices (Xcode 13.0) with Xcode 12.5: | |
| sudo ln -s /Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport/15.0 /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport | |
| # Then restart Xcode and reconnect your devices. You will need to do that for every beta of future iOS versions | |
| # (A similar approach works for older versions too, just change the version number after DeviceSupport) |
Picking the right architecture = Picking the right battles + Managing trade-offs
Some of the major topics covered in this section include:
| #ifndef NS_DESIGNATED_INITIALIZER | |
| #if __has_attribute(objc_designated_initializer) | |
| #define NS_DESIGNATED_INITIALIZER __attribute((objc_designated_initializer)) | |
| #else | |
| #define NS_DESIGNATED_INITIALIZER | |
| #endif | |
| #endif |