cJSON floating point issue

[flo90]

Hi,
i tried your code today and its working very well but cJSON is not converting a float number correctly.
You hit the problem if you try to read the dht22. The output looks like this:
{
"temp": %.0f,
"hum": %.0f
}
My current fix is to typecast the values like this:
cJSON_AddNumberToObject(root,"temp",(int8_t)data.dht22.temp);
cJSON_AddNumberToObject(root,"hum",(uint8_t)data.dht22.hum);
Maybe someone know how to fix the cJSON lib easily?!

I am using the esp-open-sdk (espressif lib v1.0.1) to compile the code.

[israellot]

The problem is the format specified in the sprintf. Our printf doesn't process the %.0f.
The solution is quite simple.

[israellot]

I've just pushed a commit that should fix it. Thank you.

[flo90]

Hi,
this didn't fix the problem because it seems that the os_sprintf just doesn't support float. In the debug output c_sprintf is used. I replaced sprintf with c_sprintf. It's working now but a little bit dirty:
{
"temp": 22.200000762,
"hum": 45.900001525
}
Furthermore sometimes there is a big whitespace between "hum": and the number. I can't show it because github removes the whitespace.

The javascript removes the waste but it's not the best solution i think.

[israellot]

Can you check if changing

#ifndef sprintf
#define sprintf os_sprintf
#endif

to

#ifndef sprintf
#define sprintf c_sprintf
#endif

solves the problem?

[flo90]

Hi,
this just leads to the same result because the preprocessor replaces sprintf with c_sprintf.
I think it's just a bad/simple float implementation.
I have two ideas to fix this special case. The sensor throws the temperature as well as the humidity as a integer number e.g 22.3°C is represented as 223. Now you can convert this value to a string and send it to the browser wich could divide the number by 10. Or you just manipulate the string and add the dot between 22 and 3.