'\" t .\" Title: upscli_get .\" Author: [FIXME: author] [see http://docbook.sf.net/el/author] .\" Generator: DocBook XSL Stylesheets v1.78.1 .\" Date: 03/02/2016 .\" Manual: NUT Manual .\" Source: Network UPS Tools 2.7.3.1 .\" Language: English .\" .TH "UPSCLI_GET" "3" "03/02/2016" "Network UPS Tools 2\&.7\&.3\&." "NUT Manual" .\" ----------------------------------------------------------------- .\" * Define some portability stuff .\" ----------------------------------------------------------------- .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .\" http://bugs.debian.org/507673 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" ----------------------------------------------------------------- .\" * set default formatting .\" ----------------------------------------------------------------- .\" disable hyphenation .nh .\" disable justification (adjust text to left margin only) .ad l .\" ----------------------------------------------------------------- .\" * MAIN CONTENT STARTS HERE * .\" ----------------------------------------------------------------- .SH "NAME" upscli_get \- retrieve data from a UPS .SH "SYNOPSIS" .sp .nf #include .fi .sp .nf int upscli_get(UPSCONN_t *ups, unsigned int numq, const char **query, unsigned int *numa, char ***answer) .fi .SH "DESCRIPTION" .sp The \fBupscli_get()\fR function takes the pointer \fIups\fR to a UPSCONN_t state structure, and the pointer \fIquery\fR to an array of \fInumq\fR query elements\&. It builds a properly\-formatted request from those elements and transmits it to \fBupsd\fR(8)\&. .sp Upon success, the response will be split into separate components\&. A pointer to those components will be returned in \fIanswer\fR\&. The number of usable answer components will be returned in \fInuma\fR\&. .SH "USES" .sp 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: .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} GET NUMLOGINS .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} GET UPSDESC .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} GET VAR .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} GET TYPE .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} GET DESC .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} GET CMDDESC .RE .SH "QUERY FORMATTING" .sp To generate a request for GET NUMLOGINS su700, you would populate query and numq as follows: .sp .if n \{\ .RS 4 .\} .nf unsigned int numq; const char *query[2]; .fi .if n \{\ .RE .\} .sp .if n \{\ .RS 4 .\} .nf query[0] = "NUMLOGINS"; query[1] = "su700"; numq = 2; .fi .if n \{\ .RE .\} .sp All escaping of special characters and quoting of elements with spaces is handled for you inside this function\&. .SH "ANSWER FORMATTING" .sp 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: .sp .if n \{\ .RS 4 .\} .nf unsigned int numa; .fi .if n \{\ .RE .\} .sp .if n \{\ .RS 4 .\} .nf numa = 3; answer[0] = "NUMLOGINS" answer[1] = "su700" answer[2] = "1" .fi .if n \{\ .RE .\} .sp Notice that the value which you seek typically starts at answer[numq]\&. .SH "ERROR CHECKING" .sp This function will check your query against the response from \fBupsd\fR(8)\&. For example, if you send "VAR" "su700" "ups\&.status", it will expect to see those at the beginning of the response\&. .sp If the results from \fBupsd\fR do not pass this case\-insensitive test against your request, this function will return an error\&. When this happens, \fBupscli_upserror\fR(3) will return \fIUPSCLI_ERR_PROTOCOL\fR\&. .SH "ANSWER ARRAY LIFETIME" .sp The pointers contained within the \fIanswer\fR array are only valid until the next call to a \fIupsclient\fR function which references them\&. If you need to use data from multiple calls, you must copy it somewhere else first\&. .sp The \fIanswer\fR 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 \fInuma\fR elements in \fIanswer\fR\&. Such behavior is undefined, and may yield bogus data or a crash\&. .sp The array will be deleted after calling \fBupscli_disconnect\fR(3)\&. Any access after that point is also undefined\&. .SH "RETURN VALUE" .sp The \fBupscli_get()\fR function returns 0 on success, or \-1 if an error occurs\&. .sp If \fBupsd\fR 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 \fBupscli_get()\fR call to return an error in that case: .sp .if n \{\ .RS 4 .\} .nf #include \&.\&.\&. signal (SIGPIPE, SIG_IGN); \&.\&.\&. .fi .if n \{\ .RE .\} .SH "SEE ALSO" .sp \fBupscli_list_start\fR(3), \fBupscli_list_next\fR(3), \fBupscli_strerror\fR(3), \fBupscli_upserror\fR(3)