ESP32 Forum

Hi,

It is probably listed somewhere but I can't find it for now: is there a limit on the length of a string you can ask for or provide via the cJSON implementation in ESP-IDF?
I am writing our own parameter storage interface layer which uses NVS to store various parameters in flash and I am wondering if the cJSON implementation can handle the maximum string parameter length of 1984 as defined by the NVS component?

Any help much appreciated.

In case you don't get an answer here, you might want to search and/or post the question to the cJSON project here:

https://github.com/DaveGamble/cJSON

Hi Zingemneire,

I'm not a cJSON expert, but I do know that internally a string is stored by cJSON as a "const char *", and that they use standard C functions like strlen() to find the length.

So I would expect that the string length limit is the maximum value of size_t minus 1, ie 2^32 - 2. So several orders of magnitude more than the NVS length limit (or the available addressable memory in an ESP32!)

As I said, there may be some secondary limiting factor I'm not aware of. But I expect not.

Hi Guys,

I got confirmation from GitHub/cJSON. There is no limit except for physical memory limits.