libxrdeveloper's documentation
gboolean xr_value_is_error_retval ( xr_value val,
int *  errcode,
char **  errmsg 
)

Check if given node is stadard XML-RPC error struct.

And store faultCode and faultString into errcode and errmsg.

Parameters
valValue node.
errcodePointer to the variable where the faultCode should be stored.
errmsgPointer to the variable where the faultString should be stored.
Returns
Function returns TRUE if node is XML-RPC error node, FALSE Otherwise.
Warning
Caller must free returned errmsg using g_free.
Documentation for libxr, Wed Apr 27 2016 22:07:49.