• buildroot中C语言使用libconfig的实例

    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

    1. /* ----------------------------------------------------------------------------
    2.    libconfig - A library for processing structured configuration files
    3.    Copyright (C) 2005-2010  Mark A Lindner
    5.    This file is part of libconfig.
    7.    This library is free software; you can redistribute it and/or
    8.    modify it under the terms of the GNU Lesser General Public License
    9.    as published by the Free Software Foundation; either version 2.1 of
    10.    the License, or (at your option) any later version.
    12.    This library is distributed in the hope that it will be useful, but
    13.    WITHOUT ANY WARRANTY; without even the implied warranty of
    14.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    15.    Lesser General Public License for more details.
    17.    You should have received a copy of the GNU Library General Public
    18.    License along with this library; if not, see
    19.    .
    20.    ----------------------------------------------------------------------------
    21. */
    22.  
    23. #include 
    24. #include 
    25. #include 
    26.  
    27. /* This example reads the configuration file 'example.cfg' and displays
    28.  * some of its contents.
    29.  */
    30.  
    31. int main(int argc, char **argv)
    32. {
    33.   config_t cfg;
    34.   config_setting_t *setting;
    35.   const char *str;
    36.  
    37.   config_init(&cfg);
    38.  
    39.   /* Read the file. If there is an error, report it and exit. */
    40.   if(! config_read_file(&cfg, "example.cfg"))
    41.   {
    42.     fprintf(stderr, "%s:%d - %s\n", config_error_file(&cfg),
    43.             config_error_line(&cfg), config_error_text(&cfg));
    44.     config_destroy(&cfg);
    45.     return(EXIT_FAILURE);
    46.   }
    47.  
    48.   /* Get the store name. */
    49.   if(config_lookup_string(&cfg, "name", &str))
    50.     printf("Store name: %s\n\n", str);
    51.   else
    52.     fprintf(stderr, "No 'name' setting in configuration file.\n");
    53.  
    54.   /* Output a list of all books in the inventory. */
    55.   setting = config_lookup(&cfg, "inventory.books");
    56.   if(setting != NULL)
    57.   {
    58.     int count = config_setting_length(setting);
    59.     int i;
    60.  
    61.     printf("%-30s  %-30s   %-6s  %s\n", "TITLE", "AUTHOR", "PRICE", "QTY");
    62.  
    63.     for(i = 0; i < count; ++i)
    64.     {
    65.       config_setting_t *book = config_setting_get_elem(setting, i);
    66.  
    67.       /* Only output the record if all of the expected fields are present. */
    68.       const char *title, *author;
    69.       double price;
    70.       int qty;
    71.  
    72.       if(!(config_setting_lookup_string(book, "title", &title)
    73.            && config_setting_lookup_string(book, "author", &author)
    74.            && config_setting_lookup_float(book, "price", &price)
    75.            && config_setting_lookup_int(book, "qty", &qty)))
    76.         continue;
    77.  
    78.       printf("%-30s  %-30s  $%6.2f  %3d\n", title, author, price, qty);
    79.     }
    80.     putchar('\n');
    81.   }
    82.  
    83.   /* Output a list of all movies in the inventory. */
    84.   setting = config_lookup(&cfg, "inventory.movies");
    85.   if(setting != NULL)
    86.   {
    87.     unsigned int count = config_setting_length(setting);
    88.     unsigned int i;
    89.  
    90.     printf("%-30s  %-10s   %-6s  %s\n", "TITLE", "MEDIA", "PRICE", "QTY");
    91.     for(i = 0; i < count; ++i)
    92.     {
    93.       config_setting_t *movie = config_setting_get_elem(setting, i);
    94.  
    95.       /* Only output the record if all of the expected fields are present. */
    96.       const char *title, *media;
    97.       double price;
    98.       int qty;
    99.  
    100.       if(!(config_setting_lookup_string(movie, "title", &title)
    101.            && config_setting_lookup_string(movie, "media", &media)
    102.            && config_setting_lookup_float(movie, "price", &price)
    103.            && config_setting_lookup_int(movie, "qty", &qty)))
    104.         continue;
    105.  
    106.       printf("%-30s  %-10s  $%6.2f  %3d\n", title, media, price, qty);
    107.     }
    108.     putchar('\n');
    109.   }
    110.  
    111.   config_destroy(&cfg);
    112.   return(EXIT_SUCCESS);
    113. }
    114.  
    115. /* eof */
    1. /* ----------------------------------------------------------------------------
    2.    libconfig - A library for processing structured configuration files
    3.    Copyright (C) 2005-2010  Mark A Lindner
    5.    This file is part of libconfig.
    7.    This library is free software; you can redistribute it and/or
    8.    modify it under the terms of the GNU Lesser General Public License
    9.    as published by the Free Software Foundation; either version 2.1 of
    10.    the License, or (at your option) any later version.
    12.    This library is distributed in the hope that it will be useful, but
    13.    WITHOUT ANY WARRANTY; without even the implied warranty of
    14.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    15.    Lesser General Public License for more details.
    17.    You should have received a copy of the GNU Library General Public
    18.    License along with this library; if not, see
    19.    .
    20.    ----------------------------------------------------------------------------
    21. */
    22.  
    23. #include 
    24. #include 
    25. #include 
    26.  
    27. /* This example reads the configuration file 'example.cfg', adds a new
    28.  * movie record to the movies list, and writes the updated configuration to
    29.  * 'updated.cfg'.
    30.  */
    31.  
    32. int main(int argc, char **argv)
    33. {
    34.   static const char *output_file = "updated.cfg";
    35.   config_t cfg;
    36.   config_setting_t *root, *setting, *movie;
    37.  
    38.   config_init(&cfg);
    39.  
    40.   /* Read the file. If there is an error, report it and exit. */
    41.   if(! config_read_file(&cfg, "example.cfg"))
    42.   {
    43.     fprintf(stderr, "%s:%d - %s\n", config_error_file(&cfg),
    44.             config_error_line(&cfg), config_error_text(&cfg));
    45.     config_destroy(&cfg);
    46.     return(EXIT_FAILURE);
    47.   }
    48.  
    49.   /* Find the 'movies' setting. Add intermediate settings if they don't yet
    50.   * exist.
    51.   */
    52.   root = config_root_setting(&cfg);
    53.  
    54.   setting = config_setting_get_member(root, "inventory");
    55.   if(!setting)
    56.     setting = config_setting_add(root, "inventory", CONFIG_TYPE_GROUP);
    57.  
    58.   setting = config_setting_get_member(setting, "movies");
    59.   if(!setting)
    60.     setting = config_setting_add(setting, "movies", CONFIG_TYPE_LIST);
    61.  
    62.   /* Create the new movie entry. */
    63.   movie = config_setting_add(setting, NULL, CONFIG_TYPE_GROUP);
    64.  
    65.   setting = config_setting_add(movie, "title", CONFIG_TYPE_STRING);
    66.   config_setting_set_string(setting, "Buckaroo Banzai");
    67.  
    68.   setting = config_setting_add(movie, "media", CONFIG_TYPE_STRING);
    69.   config_setting_set_string(setting, "DVD");
    70.  
    71.   setting = config_setting_add(movie, "price", CONFIG_TYPE_FLOAT);
    72.   config_setting_set_float(setting, 12.99);
    73.  
    74.   setting = config_setting_add(movie, "qty", CONFIG_TYPE_INT);
    75.   config_setting_set_float(setting, 20);
    76.  
    77.   config_set_options(&cfg, 0);
    78.  
    79.   /* Write out the updated configuration. */
    80.   if(! config_write_file(&cfg, output_file))
    81.   {
    82.     fprintf(stderr, "Error while writing file.\n");
    83.     config_destroy(&cfg);
    84.     return(EXIT_FAILURE);
    85.   }
    86.  
    87.   fprintf(stderr, "Updated configuration successfully written to: %s\n",
    88.           output_file);
    89.  
    90.   config_destroy(&cfg);
    91.   return(EXIT_SUCCESS);
    92. }
    93.  
    94. /* eof */
    1. /* ----------------------------------------------------------------------------
    2.    libconfig - A library for processing structured configuration files
    3.    Copyright (C) 2005-2010  Mark A Lindner
    5.    This file is part of libconfig.
    7.    This library is free software; you can redistribute it and/or
    8.    modify it under the terms of the GNU Lesser General Public License
    9.    as published by the Free Software Foundation; either version 2.1 of
    10.    the License, or (at your option) any later version.
    12.    This library is distributed in the hope that it will be useful, but
    13.    WITHOUT ANY WARRANTY; without even the implied warranty of
    14.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    15.    Lesser General Public License for more details.
    17.    You should have received a copy of the GNU Library General Public
    18.    License along with this library; if not, see
    19.    .
    20.    ----------------------------------------------------------------------------
    21. */
    22.  
    23. #include 
    24. #include 
    25. #include 
    26.  
    27. /* This example constructs a new configuration in memory and writes it to
    28.  * 'newconfig.cfg'.
    29.  */
    30.  
    31. int main(int argc, char **argv)
    32. {
    33.   static const char *output_file = "newconfig.cfg";
    34.   config_t cfg;
    35.   config_setting_t *root, *setting, *group, *array;
    36.   int i;
    37.  
    38.   config_init(&cfg);
    39.   root = config_root_setting(&cfg);
    40.  
    41.   /* Add some settings to the configuration. */
    42.   group = config_setting_add(root, "address", CONFIG_TYPE_GROUP);
    43.  
    44.   setting = config_setting_add(group, "street", CONFIG_TYPE_STRING);
    45.   config_setting_set_string(setting, "1 Woz Way");
    46.  
    47.   setting = config_setting_add(group, "city", CONFIG_TYPE_STRING);
    48.   config_setting_set_string(setting, "San Jose");
    49.  
    50.   setting = config_setting_add(group, "state", CONFIG_TYPE_STRING);
    51.   config_setting_set_string(setting, "CA");
    52.  
    53.   setting = config_setting_add(group, "zip", CONFIG_TYPE_INT);
    54.   config_setting_set_int(setting, 95110);
    55.  
    56.   array = config_setting_add(root, "numbers", CONFIG_TYPE_ARRAY);
    57.  
    58.   for(i = 0; i < 10; ++i)
    59.   {
    60.     setting = config_setting_add(array, NULL, CONFIG_TYPE_INT);
    61.     config_setting_set_int(setting, 10 * i);
    62.   }
    63.  
    64.   /* Write out the new configuration. */
    65.   if(! config_write_file(&cfg, output_file))
    66.   {
    67.     fprintf(stderr, "Error while writing file.\n");
    68.     config_destroy(&cfg);
    69.     return(EXIT_FAILURE);
    70.   }
    71.  
    72.   fprintf(stderr, "New configuration successfully written to: %s\n",
    73.           output_file);
    74.  
    75.   config_destroy(&cfg);
    76.   return(EXIT_SUCCESS);
    77. }
    78.  
    79. /* eof */

    使用的时候需要链接库Makefile中添加 -lconfig

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  • 原文地址：https://blog.csdn.net/wangmeng0804/article/details/132812050