.\"
.\" libdivecomputer
.\"
.\" Copyright (C) 2017 Kristaps Dzonsons <kristaps@bsd.lv>
.\"
.\" This library is free software; you can redistribute it and/or
.\" modify it under the terms of the GNU Lesser General Public
.\" License as published by the Free Software Foundation; either
.\" version 2.1 of the License, or (at your option) any later version.
.\"
.\" This library is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
.\" Lesser General Public License for more details.
.\"
.\" You should have received a copy of the GNU Lesser General Public
.\" License along with this library; if not, write to the Free Software
.\" Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
.\" MA 02110-1301 USA
.\"
.Dd January 5, 2017
.Dt DIVECOMPUTER 3
.Os
.Sh NAME
.Nm divecomputer
.Nd communicate with dive computers
.Sh LIBRARY
.Lb libdivecomputer
.Sh DESCRIPTION
The
.Nm divecomputer
library is a cross-platform and open source library for communication
with dive computers from various manufacturers.
Systems interfacing with
.Nm divecomputer
must link with
.Fl l Ns Ar divecomputer .
.Pp
A system wishing to query dives in a dive computer generally follows
these steps:
.Bl -enum
.It
Create a new context with
.Xr dc_context_new 3 .
This supplies a parse context: logging, error handling, etc.
Override the values with
.Xr dc_context_set_logfunc 3
and
.Xr dc_context_set_loglevel 3 .
.It
Find a descriptor for their dive computer by iterating through
.Xr dc_descriptor_iterator 3
and searching by name, vendor, or product family.
.It
Open the hardware device to which the dive computer is connected with
.Xr dc_device_open 3 ,
then invoke
.Xr dc_device_set_events 3 ,
.Xr dc_device_set_fingerprint 3 ,
and
.Xr dc_device_set_cancel 3
to set the logging events, last-seen fingerprint, and cancel routine,
respectively.
.It
Iterate over all dives with
.Xr dc_device_foreach 3 .
.It
For each iterated dive, create a new parser with
.Xr dc_parser_new 3
and set the parsed data with
.Xr dc_parser_set_data 3 .
.It
Get attributes of the parsed dive with
.Xr dc_parser_get_field 3 ,
then iterate through the dive's samples (recorded data) with
.Xr dc_parser_samples_foreach 3 .
.El
.Sh RETURN VALUES
Most
.Nm libdivecomputer
functions return with a
.Vt dc_status_t
type with the following possible values:
.Bl -tag -width Ds
.It Dv DC_STATUS_SUCCESS
Completion with success: not an error.
.It Dv DC_STATUS_DONE
End of an iterator: not an error.
.It Dv DC_STATUS_UNSUPPORTED
Feature not implemented or not supported by device.
.Po
The difference depends on the context.
Since
.Nm libdivecomputer
is largely
based on reverse engineering, we often can't even tell them apart.
.Pc
.It Dv DC_STATUS_INVALIDARGS
Invalid parameter.
Usually indicates caller bug.
.It Dv DC_STATUS_NOMEMORY
Out of memory.
.It Dv DC_STATUS_NODEVICE
Device not found.
In this context the device refers to the low-level communication device
(serial, bluetooth, irda, etc), not the dive computer.
In most cases, and especially with serial communication, we can't detect
whether the dive computer is present.
This is always detected indirectly: no response is received, and thus a
timeout error.
.It Dv DC_STATUS_NOACCESS
Access denied (again, to the low-level communication device).
.It Dv DC_STATUS_TIMEOUT
See
.Dv DC_STATUS_NODEVICE .
.It Dv DC_STATUS_IO
Any other I/O error.
.It Dv DC_STATUS_PROTOCOL
Encountered unexpected data in the communication protocol data packets,
e.g., while downloading.
.It Dv DC_STATUS_DATAFORMAT
Encountered unexpected data in the interpretation of data contents,
e.g., while parsing.
.It Dv DC_STATUS_CANCELLED
Returned when the cancel callback requested to cancel the operation.
Note that cancellation is only checked at specific (safe) points, so
it's certainly possible it may not get noticed immediately and still
return
.Dv DC_STATUS_SUCCESS .
.El
.Sh SEE ALSO
.Xr dc_buffer_new 3
.Sh AUTHORS
The
.Lb libdivecomputer
library was written by
.An Jef Driesen ,
.Mt jef@libdivecomputer.org .
These manpages were written by
.An Kristaps Dzonsons ,
.Mt kristaps@bsd.lv .