深入redis内部之redis启动过程之一

redis作为一个服务器，它的启动是从main函数开始的。redis.c

1. 进程重命名

#ifdef INIT_SETPROCTITLE_REPLACEMENT

    spt_init(argc, argv);

#endif

定义在config.h

/* Check if we can use setproctitle().  修改进程名称

 * BSD systems have support for it, we provide an implementation for

 * Linux and osx. */

#if (defined __NetBSD__ || defined __FreeBSD__ || defined __OpenBSD__) //bsd（unix的变种）宏定义

#define USE_SETPROCTITLE

#endif

#if (defined __linux || defined __APPLE__) //linux和苹果的宏定义

#define USE_SETPROCTITLE

#define INIT_SETPROCTITLE_REPLACEMENT

void spt_init(int argc, char *argv[]);

void setproctitle(const char *fmt, ...);

#endif

http://www.baike.com/wiki/BSD

BSD的开源後裔

不同的BSD操作系统针对不同的用途及用户，可应用于多种硬件构架。在政府机构中常能看到BSD的身影。虽然下面的BSD功能可能并非独有，但每种BSD在各自的领域，都逐渐具有了良好声誉，有的专注于性能，有的则以安全见长。

DragonflyBSD是最年轻的BSD，专门提供比FreeBSD更优秀的对称多处理机系统，并使内核直接支持SSI集群，以取得更好的计算效果。这个项目在此方向上，才开始数年，主要关注i386平台。

FreeBSD在BSD家族中以易用性与高性能而着称，由于主要用作微处理器架构，如i386、AMD's 64-bit i386扩展，所以FreeBSD非常关注多处理器。FreeBSD在i386和amd64服务器上，运行地非常好，当然，它也可以在其他硬件构架上运行。

NetBSD拥有特别出色的可移植性，能在多达54种平台上运行，小到嵌入式的掌上设备，大到服务器群，NetBSD甚至还在国际空间站中服务。

OpenBSD在密码学和安全方面特别出众，可移植性也很好，当然略逊于NetBSD。安全功能如OpenSSH，是由OpenBSD率先开创的。OpenBSD作为安全请求机器（security demanding machines）运行，受到好评。

必须注意的是，上面所罗列的，更多地是基于感性认识，并针对其开发焦点，并没有严格地比较规则。实际而言，每种具体的BSD都可担当许多角色任务。

2. 设置locale

    setlocale(LC_COLLATE,"");

http://manpages.ubuntu.com/manpages/lucid/en/man3/setlocale.3.html

NAME

       setlocale - set the current locale

SYNOPSIS

       #include <locale.h>

       char *setlocale(int category, const char *locale);

DESCRIPTION

       The  setlocale() function is used to set or query the program’s current

       locale.

       If locale is  not  NULL,  the  program’s  current  locale  is  modified

       according  to  the  arguments.   The argument category determines which

       parts of the program’s current locale should be modified.

       LC_ALL for all of the locale.

       LC_COLLATE

              for regular expression matching (it determines  the  meaning  of

              range expressions and equivalence classes) and string collation.

       LC_CTYPE

              for  regular  expression  matching,  character   classification,

              conversion,   case-sensitive   comparison,  and  wide  character

              functions.

       LC_MESSAGES

              for localizable natural-language messages.

       LC_MONETARY

              for monetary formatting.

       LC_NUMERIC

              for number  formatting  (such  as  the  decimal  point  and  the

              thousands separator).

       LC_TIME

              for time and date formatting.

       The  argument  locale is a pointer to a character string containing the

       required setting of category.  Such a string  is  either  a  well-known

       constant  like "C" or "da_DK" (see below), or an opaque string that was

       returned by another call of setlocale().

       If locale is "", each part of the locale that should be modified is set

       according    to   the   environment   variables.    The   details   are

       implementation-dependent.  For glibc, first (regardless  of  category),

       the  environment  variable  LC_ALL  is  inspected, next the environment

       variable with the same name  as  the  category  (LC_COLLATE,  LC_CTYPE,

       LC_MESSAGES,   LC_MONETARY,   LC_NUMERIC,   LC_TIME)  and  finally  the

       environment variable LANG.  The first existing environment variable  is

       used.   If its value is not a valid locale specification, the locale is

       unchanged, and setlocale() returns NULL.

       The locale "C" or "POSIX" is  a  portable  locale;  its  LC_CTYPE  part

       corresponds to the 7-bit ASCII character set.

       A      locale      name      is      typically      of     the     form

       language[_territory][.codeset][@modifier], where language is an ISO 639

       language  code, territory is an ISO 3166 country code, and codeset is a

       character set or encoding identifier like ISO-8859-1 or UTF-8.   For  a

       list of all supported locales, try "locale -a", cf. locale(1).

       If locale is NULL, the current locale is only queried, not modified.

       On  startup of the main program, the portable "C" locale is selected as

       default.  A program may be made portable to all locales by calling:

           setlocale(LC_ALL, "");

       after program initialization, by  using  the  values  returned  from  a

       localeconv(3)  call  for  locale-dependent  information,  by  using the

       multi-byte  and  wide  character  functions  for  text  processing   if

       MB_CUR_MAX  >  1,  and  by  using strcoll(3), wcscoll(3) or strxfrm(3),

       wcsxfrm(3) to compare strings.

RETURN VALUE

       A  successful  call  to  setlocale()  returns  an  opaque  string  that

       corresponds  to the locale set.  This string may be allocated in static

       storage.  The string returned is such that a subsequent call with  that

       string  and  its  associated  category  will  restore  that part of the

       process’s locale.  The return value is NULL if the  request  cannot  be

       honored.

CONFORMING TO

       C89, C99, POSIX.1-2001.

NOTES

       Linux  (that  is, glibc) supports the portable locales "C" and "POSIX".

       In the good old days there used to be support for the European  Latin-1

       "ISO-8859-1"  locale  (e.g.,  in  libc-4.5.21 and libc-4.6.27), and the

       Russian  "KOI-8"  (more   precisely,   "koi-8r")   locale   (e.g.,   in

       libc-4.6.27),     so    that    having    an    environment    variable

       LC_CTYPE=ISO-8859-1  sufficed  to  make  isprint(3)  return  the  right

       answer.   These  days non-English speaking Europeans have to work a bit

       harder, and must install actual locale files.

COLOPHON

       This  page  is  part of release 3.23 of the Linux man-pages project.  A

       description of the project, and information about reporting  bugs,  can

       be found at http://www.kernel.org/doc/man-pages/.