Boost | The Boost C++ Libraries | SDK library

compile time-enabled solution.

Consider whether this is useful requirement in the first place. The program isn't going to be communicating with another system at compile time. What is the case where you would need to use the serialised integer in a compile time constant context?

1. Starting at what C++ standard is there a portable standard-compliant way of performing host to network byte order conversion?

It's possible to write such function in standard C++ since C++98. That said, later standards bring tasty template goodies that make this nicer.

There isn't such function in the standard library as of the latest standard.

1. Should such a pure-c++ solution be preferred to OS specific functions such as, e.g., POSIX-htonl? (I think yes)

Advantage of POSIX is that it's less important to write tests to make sure that it works correctly.

Advantage of pure C++ function is that you don't need platform specific alternatives to those that don't conform to POSIX.

Also, the POSIX htonX are only for 16 bit and 32 bit integers. You could instead use htobeXX functions instead that are in some *BSD and in Linux (glibc).

Here is what I have been using since C+17. Some notes beforehand:

• Since endianness conversion is always¹ for purposes of serialisation, I write the result directly into a buffer. When converting to host endianness, I read from a buffer.

• I don't use CHAR_BIT because network doesn't know my byte size anyway. Network byte is an octet, and if your CPU is different, then these functions won't work. Correct handling of non-octet byte is possible but unnecessary work unless you need to support network communication on such system. Adding an assert might be a good idea.

• I prefer to call it big endian rather than "network" endian. There's a chance that a reader isn't aware of the convention that de-facto endianness of network is big.

• Instead of checking "if native endianness is X, do Y else do Z", I prefer to write a function that works with all native endianness. This can be done with bit shifts.

• Yeah, it's constexpr. Not because it needs to be, but just because it can be. I haven't been able to produce an example where dropping constexpr would produce worse code.

My knowledge comes from e.g. WG22 P0443R12 "A Unified Executors Proposal for C++".

Some differences up front: a work-guard

• does not alter the executor, instead just calling on_work_started() and on_work_finished() on it. [It is possible to have an executor on which both of these have no effect.]
• can be reset() independent of its lifetime, or that of any executor instance. Decoupled lifetime is a feature.

On the other hand, using prefer/require to apply outstanding_work sub-properties:

• modifies existing executors
• notably when copied, all copies will have the same properties. This could be dangerous for something as invasive as keeping an execution context/resources around.

However, not all properties are requirable in the first place. Doing some reconaissance using Ex defined as:

To measure the branch you are interested in and particularly the scenario when while loop becomes hot, I've used the following benchmark:

Reading a memory address does not clear the cache line.

Writing does.

So in a modern computer, there is RAM, and there are multiple layers of cache "around" the CPU (they are called L1, L2 and L3 cache, but the important part is that they are layers, and the CPU is at the middle). In a multi-core system, often the outer layers are shared; the innermost layer is usually not, and is specific to a given CPU.

Clearing the cache line means informing every other cache holding this memory "the data you own may be stale, throw it out".

Test and set writes true and atomically returns the old value. It clears the cache line, because it writes.

Test does not write. If you have another thread unsynchronized with this one, it reading the cache of this memory doesn't have to be poked.

The outer loop writes true, and exits if it replaced false. The inner loop waits until there is a false visible, then falls to outer loop. The inner loop need not clear every other cpu's cache status of the value of the atomic flag, but the outer has to (as it could change the false to true). As spinning could go on for a while, avoiding continuous cache clearing seems like a good idea.

I recently encountered a similar issue with boost after updating react native. After the panic wore off, and some good coffee, I was able to resolve by doing the following:

1. Open the /ios/.xcworkspace file in Xcode.
2. Raise the iOS Deployment Target (in my case I only bumped to 10).
3. Product > Clean Build Folder, then Product > Run.
4. Locate the boost error in the issue navigator and identify which pod the error is listed under (in my case it was RNReanimated).
5. Update the node package related to the pod (in my case, npm update react-native-reanimated
6. Finally, run pod install

After performing those steps, I was able to get my project up and running again.

Not an answer, but this might help someone else answer this. I coded this to re-create a data.frame of the size @Eric is working with.

An alternative candidate

Use unsigned math to avoid UB of int overflow and allow for taking all the - 48 out and then into a constant.

It's not related to ES version.

Update max_expansions to more than 50.

max_expansions : Maximum number of variations created.

With 3 grams letter & digits as token_chars, ideal max_expansion will be (26 alphabets + 10 digits) * 3

I think your pod install working fine and has done its job. You need to set up iPhone SDK on your mac then try to run cd ../ && react-native run-ios.

Follow this guide : React Native Environment set up on Mac OS with Xcode and Android Studio