Function pio_parse_str 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn pio_parse_str(
    text: *const c_char,
    format: *const c_char,
    errbuf: *mut c_char,
    errlen: usize,
) -> *mut PioNetwork

Parse in-memory case text of the named format into a network handle. Unlike pio_parse_file there is no path to infer from, so format is required: one of matpower/m, powermodels/pm, egret, pandapower-json/pandapower/pp, psse/raw, powerworld/aux, pslf/epc, goc3-json/goc3, surge-json/surge, or powerio-json/json (the canonical snapshot pio_to_format writes, validated on read). PyPSA CSV folders are directories, not text; parse them with pio_parse_file and from = "pypsa-csv". Read fidelity warnings attach to the handle (pio_warnings). Returns NULL on error and writes the message into errbuf. Free the handle with pio_network_free.