UPSCLI_GET(3)                     NUT Manual                     UPSCLI_GET(3)



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:

       o   GET NUMLOGINS <ups>

       o   GET UPSDESC <ups>

       o   GET VAR <ups> <var>

       o   GET TYPE <ups> <var>

       o   GET DESC <ups> <var>

       o   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)



Network UPS Tools 2.7.3.          03/02/2016                     UPSCLI_GET(3)
