setlocale配置地域化信息。
语法: char * setlocale ( int category, const char * locale );
返回值: 字符串
函数种类: 操作系统与环境
内容说明：
本函数用来配置地域的信息，设置当前程序使用的本地化信息。参数 category 有下列的选择：
LC_ALL 包括下面的全项选项都要。 LC_COLLATE 配置字符串比较，PHP 目前尚未实作出来本项。 LC_CTYPE 配置字符类别及转换。例如全变大写 strtoupper()。 LC_MONETARY 配置金融货币，PHP 目前尚未实作。 LC_NUMERIC 配置小数点后的位数。 LC_TIME 配置时间日期格式，与 strftime() 合用。 而参数 locale 若是空字符串 ""，则会使用系统环境变量的 locale 。若 locale 为零(NULL)，则不会改变地域化配置，返回当前的地域值，若系统尚未实作则返回 false。
Locales contain information on how to interpret and perform certain input/output and transformation operations taking into consideration location and language specific settings.
Most running environments have certain locale information set according to the user preferences or localization. But, independently of this system locale, on start, all C programs have the "C" locale set, which is a rather neutral locale with minimal locale information that allows the result of programs to be predictable. In order to use the default locale set in the environment, this function can be called with "" as thelocaleparameter.
The locale set on start is the same as setlocale(LC_ALL,"C") would set.
The entire default locale can be set by calling setlocale(LC_ALL,"");
C程序开始的时候的设置和 setlocale(LC_ALL,"C")相同
使用系统默认的设置调用setlocale(LC_ALL,"");
The parts of the current locale affected by a call to this function are specified by parametercategory.
Return ValueOn success, A pointer to a C string identifying the locale currently set for thecategory. Ifcategoryis LC_ALL and different parts of the locale are set to different values, the string returned gives this information in a format which may vary between compiler implementations.
