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.\" ========================================================================
.\"
.IX Title "DBFP_QUERY_DEPARTURE 3"
.TH DBFP_QUERY_DEPARTURE 3 "2016-06-10" "0.1.0" "DB timetable API"
.\" For nroff, turn off justification. Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
dbfp_query_departure \- get a list of departures at a given station from the
DB timetable API
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <dbfp.h>
\&
\& int dbfp_query_departure(struct dbfp *dbfp, char *location_id, time_t time,
\& size_t *n, struct dbfp_departure **departures);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fBdbfp_query_departure\fR queries a list of departures at a the station with the
given \fIlocation_id\fR at the given \fItime\fR using the connection metadata stored
in \fIdbfp\fR. The number of results is stored in \fIn\fR. The results are stored
in \fIdepartures\fR. The memory for the \fIdepartures\fR is allocated by the
function. The stored array contains exactly \fIn\fR elements, and is not \s-1NULL\s0
terminated.
.PP
Possible values for \fIlocation_id\fR can be retrieved using
\&\fIdbfp_query_location\fR. If \fItime\fR is zero, the current time is used.
\&\fIdbfp\fR, \fIlocation_id\fR, \fIn\fR and \fIdepartures\fR must not be \s-1NULL. \s0\fIdbfp\fR must
have been initialized with \fIdbfp_init\fR. The elements in \fIdepartures\fR should
be closed with \fIdbfp_departure_close\fR. \fIdepartures\fR should be freed by the
caller.
.PP
If the query fails, the values of \fIn\fR and \fIdepartures\fR are set to 0 and \s-1NULL\s0
respectively.
.PP
The \fBdbfp_departure\fR structure is defined as:
.PP
.Vb 9
\& struct dbfp_departure {
\& char *name;
\& char *type;
\& char *stopid;
\& char *stop;
\& time_t time;
\& char *direction;
\& char *track;
\& };
.Ve
.PP
\&\fIname\fR is the name of the departing train, \fItype\fR is the type of the train.
\&\fIstopid\fR is the \s-1ID\s0 of the stop the train departs from, and \fIstop\fR is its
name. \fItime\fR is the departure time, \fIdirection\fR the direction of the train,
and \fItrack\fR the departure track.
.SH "RETURN VALUE"
.IX Header "RETURN VALUE"
\&\fBdbfp_query_departure\fR returns zero if successful, or a non-zero error code.
Positive error codes are from \fIerrno.h\fR, negative error codes are specific
to dbfp.
.SH "ERRORS"
.IX Header "ERRORS"
.IP "\s-1EINVAL\s0" 4
.IX Item "EINVAL"
if \fIdbfp\fR, \fIlocation_id\fR, \fIn\fR or \fIdepartures\fR is \s-1NULL\s0
.IP "\s-1ENOMEM\s0" 4
.IX Item "ENOMEM"
if there is not enough memory to store the results of the query
.IP "\s-1DBFP_ERROR_CURL\s0" 4
.IX Item "DBFP_ERROR_CURL"
if an error occured during the preparation or execution of the network request
.IP "\s-1DBFP_ERROR_FORMAT\s0" 4
.IX Item "DBFP_ERROR_FORMAT"
if an error occurs during the formatting of the \s-1URL\s0
.IP "\s-1DBFP_ERROR_PARSE\s0" 4
.IX Item "DBFP_ERROR_PARSE"
if an error occurs during the parsing of the \s-1XML\s0 response
.IP "\s-1DBFP_ERROR_STRUCTURE\s0" 4
.IX Item "DBFP_ERROR_STRUCTURE"
if the \s-1API\s0 response has not the expected structure
.SH "BUGS"
.IX Header "BUGS"
Due to a typo in the \s-1DB\s0 timetable \s-1API,\s0 the \fItype\fR field of one or more of the
\&\fIdepartures\fR elements might be \s-1NULL.\s0
.PP
The time zone handling has to be checked and documented.
.SH "EXAMPLE"
.IX Header "EXAMPLE"
.Vb 4
\& #include <dbfp.h>
\& #include <stdio.h>
\& #include <stdlib.h>
\& #include <string.h>
\&
\& int main(int argc, char **argv)
\& {
\& int err = 0;
\& struct dbfp dbfp;
\& struct dbfp_departure *departures = NULL;
\& size_t n = 0;
\& size_t i;
\&
\& err = dbfp_init(&dbfp, "API key");
\& if (err)
\& goto cleanup;
\& err = dbfp_query_departure(&dbfp, "8000105", 0, &n, &departures);
\& if (err)
\& goto cleanup;
\&
\& printf("Number of matches: %zu\en", n);
\& if (n > 0)
\& printf("Departures from %s:\en", departures[0].stop);
\& for (i = 0; i < n; i++)
\& printf("%s to %s from track %s\en", departures[i].name,
\& departures[i].direction, departures[i].track);
\&
\& cleanup:
\& if (err)
\& printf("An error occured: %s\en", strerror(err));
\& for (i = 0; i < n; i++)
\& dbfp_departure_close(&departures[i]);
\& free(departures);
\& dbfp_close(&dbfp);
\&
\& return err ? EXIT_FAILURE : EXIT_SUCCESS;
\& }
.Ve
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fIdbfp_init\fR\|(3), \fIdbfp_departure_close\fR\|(3)
|
