Difference between MJSON and Frozen?

[Harvie]

Hello,
cessanta hosts two JSON libraries:
https://github.com/cesanta/mjson/ (~1.0 kLoC)
https://github.com/cesanta/frozen/ (~1.5 kLoC)

Both seem to be tiny. Is there any reccomendation on which library to use for specific use cases?
I think it might be useful to cross-reference and mention this in READMEs of both libraries, so users can make better decisions when choosing between the two.

Thanks.

[cpq]

1. Different way for scanning values: frozen scans using {a: %d} format, mjson uses jsonpath $.a
2. mjson supports a bit less conversion specifiers
3. mjson does not use libc printf as a dependency - it never falls back to snprintf(). It implements its own low level printing routines, like mjson_print_dbl(), and therefore works on a wider set of platforms - even where floating point support in libc is absent
4. mjson has a very lightweight built-in json-rpc API
5. mjson is MIT, frozen in Apache2

We'd recommend using mjson - unless you're using Mongoose OS, where frozen is built-in.

[Harvie]

mjson does not use libc printf as a dependency - it never falls back to snprintf(). It implements its own low level printing routines, like mjson_print_dbl().

This is interresting given the fact that snprintf() (any any of calls from *printf() family) is not async signal safe (see man signal-safety). Does this make mjson async signal safe? This basicaly means that such function (eg. printf) shares some buffer between threads and uses mutex to serialize access to it, so if one of the threads get interrupted (by signal, or ISR) the other threads can become deadlocked because mutex is left locked by thread which is no longer running.

[cpq]

@Harvie mjson does not use any shared / static buffers or variables. It is safe to use it from multiple threads/tasks.