libsigrok/backend.c

190 lines
5.2 KiB
C

/*
* This file is part of the sigrok project.
*
* Copyright (C) 2010-2012 Bert Vermeulen <bert@biot.com>
* Copyright (C) 2012 Peter Stuge <peter@stuge.se>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <glib.h>
#include "config.h" /* Needed for HAVE_LIBUSB_1_0 and others. */
#include "libsigrok.h"
#include "libsigrok-internal.h"
/**
* @mainpage libsigrok API
*
* @section sec_intro Introduction
*
* The <a href="http://sigrok.org">sigrok</a> project aims at creating a
* portable, cross-platform, Free/Libre/Open-Source signal analysis software
* suite that supports various device types (such as logic analyzers,
* oscilloscopes, multimeters, and more).
*
* <a href="http://sigrok.org/wiki/Libsigrok">libsigrok</a> is a shared
* library written in C which provides the basic API for talking to
* <a href="http://sigrok.org/wiki/Supported_hardware">supported hardware</a>
* and reading/writing the acquired data into various
* <a href="http://sigrok.org/wiki/Input_output_formats">input/output
* file formats</a>.
*
* @section sec_api API reference
*
* See the "Modules" page for an introduction to various libsigrok
* related topics and the detailed API documentation of the respective
* functions.
*
* You can also browse the API documentation by file, or review all
* data structures.
*
* @section sec_mailinglists Mailing lists
*
* There are two mailing lists for sigrok/libsigrok: <a href="https://lists.sourceforge.net/lists/listinfo/sigrok-devel">sigrok-devel</a> and <a href="https://lists.sourceforge.net/lists/listinfo/sigrok-commits">sigrok-commits</a>.
*
* @section sec_irc IRC
*
* You can find the sigrok developers in the
* <a href="irc://chat.freenode.net/sigrok">\#sigrok</a>
* IRC channel on Freenode.
*
* @section sec_website Website
*
* <a href="http://sigrok.org/wiki/Libsigrok">sigrok.org/wiki/Libsigrok</a>
*/
/**
* @file
*
* Initializing and shutting down libsigrok.
*/
/**
* @defgroup grp_init Initialization
*
* Initializing and shutting down libsigrok.
*
* Before using any of the libsigrok functionality, sr_init() must
* be called to initialize the library, which will return a struct sr_context
* when the initialization was successful.
*
* When libsigrok functionality is no longer needed, sr_exit() should be
* called, which will (among other things) free the struct sr_context.
*
* Example for a minimal program using libsigrok:
*
* @code{.c}
* #include <stdio.h>
* #include <libsigrok/libsigrok.h>
*
* int main(int argc, char **argv)
* {
* int ret;
* struct sr_context *sr_ctx;
*
* if ((ret = sr_init(&sr_ctx)) != SR_OK) {
* printf("Error initializing libsigrok (%s): %s.",
* sr_strerror_name(ret), sr_strerror(ret));
* return 1;
* }
*
* // Use libsigrok functions here...
*
* if ((ret = sr_exit(sr_ctx)) != SR_OK) {
* printf("Error shutting down libsigrok (%s): %s.",
* sr_strerror_name(ret), sr_strerror(ret));
* return 1;
* }
*
* return 0;
* }
* @endcode
*
* @{
*/
/**
* Initialize libsigrok.
*
* This function must be called before any other libsigrok function.
*
* @param ctx Pointer to a libsigrok context struct pointer. Must not be NULL.
* This will be a pointer to a newly allocated libsigrok context
* object upon success, and is undefined upon errors.
*
* @return SR_OK upon success, a (negative) error code otherwise. Upon errors
* the 'ctx' pointer is undefined and should not be used. Upon success,
* the context will be free'd by sr_exit() as part of the libsigrok
* shutdown.
*/
SR_API int sr_init(struct sr_context **ctx)
{
int ret = SR_ERR;
struct sr_context *context;
if (!ctx) {
sr_err("%s(): libsigrok context was NULL.", __func__);
return SR_ERR;
}
/* + 1 to handle when struct sr_context has no members. */
context = g_try_malloc0(sizeof(struct sr_context) + 1);
if (!context) {
ret = SR_ERR_MALLOC;
goto done;
}
#ifdef HAVE_LIBUSB_1_0
ret = libusb_init(&context->libusb_ctx);
if (LIBUSB_SUCCESS != ret) {
sr_err("libusb_init() returned %s.\n", libusb_error_name(ret));
goto done;
}
#endif
*ctx = context;
ret = SR_OK;
done:
return ret;
}
/**
* Shutdown libsigrok.
*
* @param ctx Pointer to a libsigrok context struct. Must not be NULL.
*
* @return SR_OK upon success, a (negative) error code otherwise.
*/
SR_API int sr_exit(struct sr_context *ctx)
{
if (!ctx) {
sr_err("%s(): libsigrok context was NULL.", __func__);
return SR_ERR;
}
sr_hw_cleanup_all();
#ifdef HAVE_LIBUSB_1_0
libusb_exit(ctx->libusb_ctx);
#endif
g_free(ctx);
return SR_OK;
}
/** @} */