2

I have to admit that I can't really use this function.

I'm trying to format some json but it crashing all the time my arduino:

char response[300];
tmp = "123";
snprintf(response, 300, "[{Name:'Furnace',Value=%s,Alarm={MinValue=%s,MaxValue=%s}},{Name:'Room',Value=%s,Alarm={MinValue=%s,MaxValue=%s}}]", tmp);

How should I use this function properly?

Nick Gammon ♦
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asked Mar 8, 2015 at 21:43
1
  • That's not JSON. Commented Mar 8, 2015 at 21:52

1 Answer 1

2 
char response[300];
tmp = "123";
snprintf(response, 300,
 "[{Name:'Furnace',Value=%s,Alarm={MinValue=%s,MaxValue=%s}},"
 "{Name:'Room',Value=%s,Alarm={MinValue=%s,MaxValue=%s}}]",
 tmp, tmp, tmp, tmp, tmp, tmp);

In other words, you should add, after the format string, as many extra parameters as there are %s in the format string.

PS: This looks like JSON, but it is not really valid JSON. The format below should give valid JSON:

"[{\"Name\":\"Furnace\",\"Value\":%s,"
"\"Alarm\":{\"MinValue\":%s,\"MaxValue\":%s}},"
"{\"Name\":\"Room\",\"Value\":%s,"
"\"Alarm\":{\"MinValue\":%s,\"MaxValue\":%s}}]",
answered Mar 8, 2015 at 21:54

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