Single-thread Mode

[michaeleisel]

For some use cases like mine (where there's a bunch of core pinning for different threads going on), it's desirable to not spawn any threads and just run everything on the calling thread. This is done, for example, in https://github.com/ben-strasser/fast-cpp-csv-parser by defining CSV_IO_NO_THREAD. It would be great if csv-parser had this functionality too, and ideally not as a preprocessor flag but as a per-parser-object setting.

[vincentlaucsb]

In #301 I added a similar macro CSV_ENABLE_THREADS.

I'm keeping this issue open since you specifically asked for a runtime flag, not a macro.

I'm curious what your specific workflow is. I'm open to having this be a runtime flag since I'd like to limit the amount of macros inside actual class and function definitions, and I can see some scenarios where runtime polymorphic behavior is desirable (e.g. disable threading for very small files, since the thread overhead is probably not worth it).

[michaeleisel]

Thanks for doing that, it would've solved my use case, although I am no longer working on that project. There are many reasons why having a single thread is desirable (e.g., having the consumer be the one to manage the multithreading of CSV parsers, or to ensure a certain total # of threads for the program so that all will get preempted less).