NAME

       upscli_get - retrieve data from a UPS

SYNOPSIS

       #include <upsclient.h>

       int upscli_get(UPSCONN_t *ups, unsigned int numq, const char **query,
                              unsigned int *numa, char ***answer)

DESCRIPTION

       The upscli_get() function takes the pointer ups to a UPSCONN_t state structure, and the
       pointer query to an array of numq query elements. It builds a properly-formatted request
       from those elements and transmits it to upsd(8).

       Upon success, the response will be split into separate components. A pointer to those
       components will be returned in answer. The number of usable answer components will be
       returned in numa.

USES

       This function implements the "GET" command in the protocol. As a result, you can use it to
       request many different things from the server. Some examples are:

       •   GET NUMLOGINS <ups>

       •   GET UPSDESC <ups>

       •   GET VAR <ups> <var>

       •   GET TYPE <ups> <var>

       •   GET DESC <ups> <var>

       •   GET CMDDESC <ups> <cmd>

QUERY FORMATTING

       To generate a request for GET NUMLOGINS su700, you would populate query and numq as
       follows:

           unsigned int numq;
           const char *query[2];

           query[0] = "NUMLOGINS";
           query[1] = "su700";
           numq = 2;

       All escaping of special characters and quoting of elements with spaces is handled for you
       inside this function.

ANSWER FORMATTING

       The raw response from upsd to the above query would be NUMLOGINS su700 1. Since this is
       split up for you, the values work out like this:

           unsigned int numa;

           numa = 3;
           answer[0] = "NUMLOGINS"
           answer[1] = "su700"
           answer[2] = "1"

       Notice that the value which you seek typically starts at answer[numq].

ERROR CHECKING

       This function will check your query against the response from upsd(8). For example, if you
       send "VAR" "su700" "ups.status", it will expect to see those at the beginning of the
       response.

       If the results from upsd do not pass this case-insensitive test against your request, this
       function will return an error. When this happens, upscli_upserror(3) will return
       UPSCLI_ERR_PROTOCOL.

ANSWER ARRAY LIFETIME

       The pointers contained within the answer array are only valid until the next call to a
       upsclient function which references them. If you need to use data from multiple calls, you
       must copy it somewhere else first.

       The answer array and its elements may change locations, so you must not rely on previous
       addresses. You must only use the addresses which were returned by the most recent call.
       You also must not attempt to use more than numa elements in answer. Such behavior is
       undefined, and may yield bogus data or a crash.

       The array will be deleted after calling upscli_disconnect(3). Any access after that point
       is also undefined.

RETURN VALUE

       The upscli_get() function returns 0 on success, or -1 if an error occurs.

       If upsd disconnects, you may need to handle or ignore SIGPIPE in order to prevent your
       program from terminating the next time that the library writes to the disconnected socket.
       The following code in your initialization function will allow the upscli_get() call to
       return an error in that case:

           #include <signal.h>
           ...
           signal (SIGPIPE, SIG_IGN);
           ...

SEE ALSO

       upscli_list_start(3), upscli_list_next(3), upscli_strerror(3), upscli_upserror(3)