> Especially when you compare C++ to other languages, there’s a pretty strong argument to be made for a more inclusive and even all-encompassing standard library - look at the richness of the standard libraries for Java or Python.
What is that argument? And even if you accept that argument, can we execute? That is, will the result be at least of a similar quality, or will it be riddled with subtle gotchas and sharp edges like the existing C++ standard library?
> So, what should go in the standard library? Fundamentals. Things that can only be done with compiler support, or compile-time things that are so subtle that only the standard should be trusted to get it right. Vocabulary. Time, vector, string. Concurrency. Mutex, future, executors.
Can the standard be trusted to get these things right?
- Vocabulary: There's a fair amount of depth to what "right" means for vector and string in many contexts, so the standard can only be trusted to get them "right" in cases that have very few constraints (where it can do admirably). Implementors have been known to break the ABIs of std::vector and/or std::string between compiler/library versions, so they aren't appropriate types to use in interfaces.
- Concurrency: Leaving aside the C++ memory model, the library support should largely be avoided. For an example of why: std::condition_variable's ctor either takes another condvar or no arguments. pthread_cond_init takes a pthread_condattr_t. On Linux, this can specify a clock. On my system, if you want to wait for a second according to CLOCK_MONOTONIC/std::chrono::steady_clock on my implementation, condition_variable::wait_until will convert your time to CLOCK_REALTIME/system_clock (by now()ing both clocks and adding the difference to the deadline you supplied) and sleep until the converted time. That's not what you asked for; it's totally wrong and possibly dangerous.
> Especially when you compare C++ to other languages, there’s a pretty strong argument to be made for a more inclusive and even all-encompassing standard library - look at the richness of the standard libraries for Java or Python.
What is that argument? And even if you accept that argument, can we execute? That is, will the result be at least of a similar quality, or will it be riddled with subtle gotchas and sharp edges like the existing C++ standard library?
> So, what should go in the standard library? Fundamentals. Things that can only be done with compiler support, or compile-time things that are so subtle that only the standard should be trusted to get it right. Vocabulary. Time, vector, string. Concurrency. Mutex, future, executors.
Can the standard be trusted to get these things right?
- Vocabulary: There's a fair amount of depth to what "right" means for vector and string in many contexts, so the standard can only be trusted to get them "right" in cases that have very few constraints (where it can do admirably). Implementors have been known to break the ABIs of std::vector and/or std::string between compiler/library versions, so they aren't appropriate types to use in interfaces.
- Concurrency: Leaving aside the C++ memory model, the library support should largely be avoided. For an example of why: std::condition_variable's ctor either takes another condvar or no arguments. pthread_cond_init takes a pthread_condattr_t. On Linux, this can specify a clock. On my system, if you want to wait for a second according to CLOCK_MONOTONIC/std::chrono::steady_clock on my implementation, condition_variable::wait_until will convert your time to CLOCK_REALTIME/system_clock (by now()ing both clocks and adding the difference to the deadline you supplied) and sleep until the converted time. That's not what you asked for; it's totally wrong and possibly dangerous.