1. C++API 头文件 #include <libconfig.h++> ，命名空间：using namespace libconfig;
2.多线程使用问题：
（1）libconfig是完全可重入的,库中函数不使用全局变量和不保持成功调用间的状态。所以两个独立配置文件在两个不同线程间并发操作可以是安全的；
（2）libconfig是线程不安全，libconfig不考虑系统线程模型。所以一个配置文件的实例被多个线程获取，必须使用同步机制（例如读写锁或互斥锁）来保护。
（3）libconfig不是异步安全，不能在信号句柄中调用
（4）libconfig不能保证取消安全。因为它不知道主机系统的线程模型，库不包含任何线程取消点。在大多数情况下这将不是多线程程序的问题。但是，请注意一些库中的例程（即那些从/到文件读取/写入配置的程序）流）使用可能会阻止的C库例程执行I/O；是否这些C库例程是取消安全的，取决于主机系统。
3.C++API
C++API使用Config类和Setting类，因为不提供公有的copy constructor or assignment operator，所以在函数参数中传递时使用引用或指针方式
4.使用方法（使用官方example）：
配置文件：
// An example configuration file that stores information about a store.// Basic store information:
name = "Books, Movies & More";// Store inventory:
inventory =
{
books = ( { title = "Treasure Island";
author = "Robert Louis Stevenson";
price = 29.99;
qty = ; },
{ title = "Snow Crash";
author = "Neal Stephenson";
price = 9.99;
qty = ; }
); movies = ( { title = "Brazil";
media = "DVD";
price = 19.99;
qty = ; },
{ title = "The City of Lost Children";
media = "DVD";
price = 18.99;
qty = ; },
{ title = "Memento";
media = "Blu-Ray";
price = 24.99;
qty = ;
},
{ title = "Howard the Duck"; }
);
};// Store hours:
hours =
{
mon = { open = ; close = ; };
tue = { open = ; close = ; };
wed = { open = ; close = ; };
thu = { open = ; close = ; };
fri = { open = ; close = ; };
sat = { open = ; close = ; };
sun = { open = ; close = ; };
};
C++读取配置程序：
#include <cstdlib>
#include <libconfig.h++>
#include <iostream>
#include <iomanip>using namespace std;
using namespace libconfig;int main(){
Config cfg; //1.声明 Config对象 cfg.readFile("example.cfg"); //读取配置文件 // Get the store name.
try
{
string name = cfg.lookup("name");
cout << "Store name: " << name << endl << endl;
}
catch(const SettingNotFoundException &nfex) //配置没找到会有SettingNotFoundException 异常
{
cerr << "No 'name' setting in configuration file." << endl;
}
// Get the store name.
try
{
string name = cfg.lookup("name");
cout << "Store name: " << name << endl << endl;
}
catch(const SettingNotFoundException &nfex)
{
cerr << "No 'name' setting in configuration file." << endl;
} const Setting& root = cfg.getRoot(); // Output a list of all books in the inventory.
try
{
const Setting &books = root["inventory"]["books"];
int count = books.getLength(); cout << setw() << left << "TITLE" << " "
<< setw() << left << "AUTHOR" << " "
<< setw() << left << "PRICE" << " "
<< "QTY"
<< endl; for(int i = ; i < count; ++i)
{
const Setting &book = books[i]; // Only output the record if all of the expected fields are present.
string title, author;
double price;
int qty; if(!(book.lookupValue("title", title)
&& book.lookupValue("author", author)
&& book.lookupValue("price", price)
&& book.lookupValue("qty", qty)))
continue; cout << setw() << left << title << " "
<< setw() << left << author << " "
<< '$' << setw() << right << price << " "
<< qty
<< endl;
}
cout << endl;
}
catch(const SettingNotFoundException &nfex)
{
// Ignore.
} // Output a list of all books in the inventory.
try
{
const Setting &movies = root["inventory"]["movies"];
int count = movies.getLength(); cout << setw() << left << "TITLE" << " "
<< setw() << left << "MEDIA" << " "
<< setw() << left << "PRICE" << " "
<< "QTY"
<< endl; for(int i = ; i < count; ++i)
{
const Setting &movie = movies[i]; // Only output the record if all of the expected fields are present.
string title, media;
double price;
int qty; if(!(movie.lookupValue("title", title)
&& movie.lookupValue("media", media)
&& movie.lookupValue("price", price)
&& movie.lookupValue("qty", qty)))
continue; cout << setw() << left << title << " "
<< setw() << left << media << " "
<< '$' << setw() << right << price << " "
<< qty
<< endl;
}
cout << endl;
}
catch(const SettingNotFoundException &nfex)
{
// Ignore.
}
return ;
}
5.常用Config类方法：
（1）Method on Config: Setting & getRoot () const
This method returns the root setting for the configuration, which is a group.
（2）
Method on Config: Setting & lookup (const std::string &path) constMethod on Config: Setting & lookup (const char * path) const
These methods locate the setting specified by the path path. If the requested setting is not found, a SettingNotFoundException is thrown.
（3）
Method on Config: bool lookupValue (const char *path, bool &value) constMethod on Config: bool lookupValue (const std::string &path, bool &value) constMethod on Config: bool lookupValue (const char *path, int &value) constMethod on Config: bool lookupValue (const std::string &path, int &value) constMethod on Config: bool lookupValue (const char *path, unsigned int &value) constMethod on Config: bool lookupValue (const std::string &path, unsigned int &value) constMethod on Config: bool lookupValue (const char *path, long long &value) constMethod on Config: bool lookupValue (const std::string &path, long long &value) constMethod on Config: bool lookupValue (const char *path, float &value) constMethod on Config: bool lookupValue (const std::string &path, float &value) constMethod on Config: bool lookupValue (const char *path, double &value) constMethod on Config: bool lookupValue (const std::string &path, double &value) constMethod on Config: bool lookupValue (const char *path, const char *&value) constMethod on Config: bool lookupValue (const std::string &path, const char *&value) constMethod on Config: bool lookupValue (const char *path, std::string &value) constMethod on Config: bool lookupValue (const std::string &path, std::string &value) const
