首先在buildroot中开启libconfig
在config中添加
BR2_PACKAGE_LIBCONFIG=y
下面是官方给出来的3个实例
cpp
/* ----------------------------------------------------------------------------
libconfig - A library for processing structured configuration files
Copyright (C) 2005-2010 Mark A Lindner
This file is part of libconfig.
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 Library General Public
License along with this library; if not, see
<http://www.gnu.org/licenses/>.
----------------------------------------------------------------------------
*/
#include <stdio.h>
#include <stdlib.h>
#include <libconfig.h>
/* This example reads the configuration file 'example.cfg' and displays
* some of its contents.
*/
int main(int argc, char **argv)
{
config_t cfg;
config_setting_t *setting;
const char *str;
config_init(&cfg);
/* Read the file. If there is an error, report it and exit. */
if(! config_read_file(&cfg, "example.cfg"))
{
fprintf(stderr, "%s:%d - %s\n", config_error_file(&cfg),
config_error_line(&cfg), config_error_text(&cfg));
config_destroy(&cfg);
return(EXIT_FAILURE);
}
/* Get the store name. */
if(config_lookup_string(&cfg, "name", &str))
printf("Store name: %s\n\n", str);
else
fprintf(stderr, "No 'name' setting in configuration file.\n");
/* Output a list of all books in the inventory. */
setting = config_lookup(&cfg, "inventory.books");
if(setting != NULL)
{
int count = config_setting_length(setting);
int i;
printf("%-30s %-30s %-6s %s\n", "TITLE", "AUTHOR", "PRICE", "QTY");
for(i = 0; i < count; ++i)
{
config_setting_t *book = config_setting_get_elem(setting, i);
/* Only output the record if all of the expected fields are present. */
const char *title, *author;
double price;
int qty;
if(!(config_setting_lookup_string(book, "title", &title)
&& config_setting_lookup_string(book, "author", &author)
&& config_setting_lookup_float(book, "price", &price)
&& config_setting_lookup_int(book, "qty", &qty)))
continue;
printf("%-30s %-30s $%6.2f %3d\n", title, author, price, qty);
}
putchar('\n');
}
/* Output a list of all movies in the inventory. */
setting = config_lookup(&cfg, "inventory.movies");
if(setting != NULL)
{
unsigned int count = config_setting_length(setting);
unsigned int i;
printf("%-30s %-10s %-6s %s\n", "TITLE", "MEDIA", "PRICE", "QTY");
for(i = 0; i < count; ++i)
{
config_setting_t *movie = config_setting_get_elem(setting, i);
/* Only output the record if all of the expected fields are present. */
const char *title, *media;
double price;
int qty;
if(!(config_setting_lookup_string(movie, "title", &title)
&& config_setting_lookup_string(movie, "media", &media)
&& config_setting_lookup_float(movie, "price", &price)
&& config_setting_lookup_int(movie, "qty", &qty)))
continue;
printf("%-30s %-10s $%6.2f %3d\n", title, media, price, qty);
}
putchar('\n');
}
config_destroy(&cfg);
return(EXIT_SUCCESS);
}
/* eof */
cpp
/* ----------------------------------------------------------------------------
libconfig - A library for processing structured configuration files
Copyright (C) 2005-2010 Mark A Lindner
This file is part of libconfig.
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 Library General Public
License along with this library; if not, see
<http://www.gnu.org/licenses/>.
----------------------------------------------------------------------------
*/
#include <stdio.h>
#include <stdlib.h>
#include <libconfig.h>
/* This example reads the configuration file 'example.cfg', adds a new
* movie record to the movies list, and writes the updated configuration to
* 'updated.cfg'.
*/
int main(int argc, char **argv)
{
static const char *output_file = "updated.cfg";
config_t cfg;
config_setting_t *root, *setting, *movie;
config_init(&cfg);
/* Read the file. If there is an error, report it and exit. */
if(! config_read_file(&cfg, "example.cfg"))
{
fprintf(stderr, "%s:%d - %s\n", config_error_file(&cfg),
config_error_line(&cfg), config_error_text(&cfg));
config_destroy(&cfg);
return(EXIT_FAILURE);
}
/* Find the 'movies' setting. Add intermediate settings if they don't yet
* exist.
*/
root = config_root_setting(&cfg);
setting = config_setting_get_member(root, "inventory");
if(!setting)
setting = config_setting_add(root, "inventory", CONFIG_TYPE_GROUP);
setting = config_setting_get_member(setting, "movies");
if(!setting)
setting = config_setting_add(setting, "movies", CONFIG_TYPE_LIST);
/* Create the new movie entry. */
movie = config_setting_add(setting, NULL, CONFIG_TYPE_GROUP);
setting = config_setting_add(movie, "title", CONFIG_TYPE_STRING);
config_setting_set_string(setting, "Buckaroo Banzai");
setting = config_setting_add(movie, "media", CONFIG_TYPE_STRING);
config_setting_set_string(setting, "DVD");
setting = config_setting_add(movie, "price", CONFIG_TYPE_FLOAT);
config_setting_set_float(setting, 12.99);
setting = config_setting_add(movie, "qty", CONFIG_TYPE_INT);
config_setting_set_float(setting, 20);
config_set_options(&cfg, 0);
/* Write out the updated configuration. */
if(! config_write_file(&cfg, output_file))
{
fprintf(stderr, "Error while writing file.\n");
config_destroy(&cfg);
return(EXIT_FAILURE);
}
fprintf(stderr, "Updated configuration successfully written to: %s\n",
output_file);
config_destroy(&cfg);
return(EXIT_SUCCESS);
}
/* eof */
cpp
/* ----------------------------------------------------------------------------
libconfig - A library for processing structured configuration files
Copyright (C) 2005-2010 Mark A Lindner
This file is part of libconfig.
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 Library General Public
License along with this library; if not, see
<http://www.gnu.org/licenses/>.
----------------------------------------------------------------------------
*/
#include <stdio.h>
#include <stdlib.h>
#include <libconfig.h>
/* This example constructs a new configuration in memory and writes it to
* 'newconfig.cfg'.
*/
int main(int argc, char **argv)
{
static const char *output_file = "newconfig.cfg";
config_t cfg;
config_setting_t *root, *setting, *group, *array;
int i;
config_init(&cfg);
root = config_root_setting(&cfg);
/* Add some settings to the configuration. */
group = config_setting_add(root, "address", CONFIG_TYPE_GROUP);
setting = config_setting_add(group, "street", CONFIG_TYPE_STRING);
config_setting_set_string(setting, "1 Woz Way");
setting = config_setting_add(group, "city", CONFIG_TYPE_STRING);
config_setting_set_string(setting, "San Jose");
setting = config_setting_add(group, "state", CONFIG_TYPE_STRING);
config_setting_set_string(setting, "CA");
setting = config_setting_add(group, "zip", CONFIG_TYPE_INT);
config_setting_set_int(setting, 95110);
array = config_setting_add(root, "numbers", CONFIG_TYPE_ARRAY);
for(i = 0; i < 10; ++i)
{
setting = config_setting_add(array, NULL, CONFIG_TYPE_INT);
config_setting_set_int(setting, 10 * i);
}
/* Write out the new configuration. */
if(! config_write_file(&cfg, output_file))
{
fprintf(stderr, "Error while writing file.\n");
config_destroy(&cfg);
return(EXIT_FAILURE);
}
fprintf(stderr, "New configuration successfully written to: %s\n",
output_file);
config_destroy(&cfg);
return(EXIT_SUCCESS);
}
/* eof */使用的时候需要链接库Makefile中添加 -lconfig