int upscli_list_next(UPSCONN_t *ups, int numq, const char **query, int *numa, char ***answer)
The upscli_list_next() function takes the pointer ups to a UPSCONN_t state structure, and the pointer query to an array of numq query elements. It performs a read from the network and expects to find either another list item or the end of a list.
You must call upscli_list_start(3) before calling this function.
This function will return 1 and set values in numa and answer if a list item is received. If the list is done, it will return 0, and the values in numa and answer are undefined.
Calling this function after it returns something other than 1 is undefined.
You may not change the values of numq or query between the call to upscli_list_start(3) and the first call to this function. You also may not change the values between calls to this function.
This function checks the response from upsd(8) against your query. If the response is not part of the list you have requested, it will return an error code.
When this happens, upscli_upserror(3) will return UPSCLI_ERR_PROTOCOL.
The upscli_list_next() function returns 1 when list data is present, 0 if the list is finished, or -1 if an error occurs.
It is possible to have an empty list. The function will return 0 for its first call in that case.