Question 1

How to parse nested JSON arrays with Frozen?

Accepted Answer

Use json_scanf_array_elem() to iterate over array elements, then parse each with json_scanf(). The README provides an example for scanning arrays of objects, like iterating over .a in a JSON string.

Question 2

Can Frozen handle JSON from HTTP responses on microcontrollers?

Accepted Answer

Yes, Frozen's small footprint makes it suitable for parsing JSON from web APIs in embedded systems, especially when paired with lightweight HTTP clients, as it's used in Mongoose OS for IoT devices.

Question 3

Frozen or cJSON: which is better for embedded C projects?

Accepted Answer

Frozen is more minimal and dependency-free, perfect for extreme memory constraints, while cJSON offers a richer feature set but larger footprint. Choose Frozen if code size is critical; cJSON for more functionality out-of-the-box.

Question 4

How to pretty-print JSON output with Frozen?

Accepted Answer

Use json_prettify() for strings or json_prettify_file() for files to format JSON human-readably. The README shows examples of writing JSON to a file and then prettifying it for configuration files.

Question 5

Does Frozen support modifying specific keys in a JSON string?

Accepted Answer

Yes, json_setf() allows in-place updates by specifying a JSON path, such as .a for a key, and can add or delete keys. The API reference includes examples like updating .a to a new value in an existing JSON string.

Question 6

What happens if I use %f in json_printf with minimal mode?

Accepted Answer

In minimal mode (-DJSON_MINIMAL=1), floating-point support is disabled, so %f specifiers will not work correctly. The README warns that only integer numbers are supported in this configuration to reduce footprint.

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