如何使用 libconfig 写入配置文件？

Question

我一直在使用 libconfig++ 库来读取配置文件，并且效果很好。此外，还有足够多的关于 API 的信息，这些信息有助于使用 c++ 从结构化配置文件中读取操作。但是，我在文档中找不到任何可以帮助我了解如何写回配置文件的内容。当然，很少有函数可以帮助我们使用 C 实现它，但对于 C++ 则没有。有没有人有任何想法或者可以指出我一些文档。 无论如何，这是 libconfig 的文档 http://www.hyperrealm.com/libconfig/libconfig_manual.html

Answer 1

libconfig/examples/c/example3.c 中有一个很好的例子

将 C 库替换为 C++ 库并不复杂。

这是所要求的完整代码：

/* ----------------------------------------------------------------------------
   libconfig - A library for processing structured configuration files
   Copyright (C) 2005-2018  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 */