'\" t
.\"     Title: upscli_list_start
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
.\"      Date: 03/02/2016
.\"    Manual: NUT Manual
.\"    Source: Network UPS Tools 2.7.3.1
.\"  Language: English
.\"
.TH "UPSCLI_LIST_START" "3" "03/02/2016" "Network UPS Tools 2\&.7\&.3\&." "NUT Manual"
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.SH "NAME"
upscli_list_start \- begin multi\-item retrieval from a UPS
.SH "SYNOPSIS"
.sp
.nf
#include <upsclient\&.h>
.fi
.sp
.nf
int upscli_list_start(UPSCONN_t *ups, unsigned int numq, const char **query)
.fi
.SH "DESCRIPTION"
.sp
The \fBupscli_list_start()\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 caller must call \fBupscli_list_next\fR(3) to retrieve the elements of the list\&. Failure to retrieve the list will most likely result in the client getting out of sync with the server due to buffered data\&.
.SH "USES"
.sp
This function implements the "LIST" 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
.\}
LIST UPS
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
LIST VAR <ups>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
LIST RW <ups>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
LIST CMD <ups>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
LIST ENUM <ups> <var>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
LIST RANGE <ups> <var>
.RE
.SH "QUERY FORMATTING"
.sp
To see the list of variables on a UPS called \fIsu700\fR, the protocol command would be LIST VAR su700\&. To start that list with this function, 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] = "VAR";
query[1] = "su700";
numq = 2;
.fi
.if n \{\
.RE
.\}
.sp
All escaping of special characters and quoting of elements with spaces are handled for you inside this function\&.
.SH "ERROR CHECKING"
.sp
This function checks the response from \fBupsd\fR(8) against your query\&. If it is not starting a list, or is starting the wrong type of list, it will return an error code\&.
.sp
When this happens, \fBupscli_upserror\fR(3) will return UPSCLI_ERR_PROTOCOL\&.
.SH "RETURN VALUE"
.sp
The \fBupscli_list_start()\fR function returns 0 on success, or \-1 if an error occurs\&.
.SH "SEE ALSO"
.sp
\fBupscli_fd\fR(3), \fBupscli_get\fR(3), \fBupscli_readline\fR(3), \fBupscli_sendline\fR(3), \fBupscli_ssl\fR(3), \fBupscli_strerror\fR(3), \fBupscli_upserror\fR(3)