开始第一段：
int
main(int argc, char *argv[])
{
/*
* options with no short version return a low integer, the rest return
* their short version value
*/
static struct option long_options[] = {
{"pgdata", required_argument, NULL, 'D'},
{"encoding", required_argument, NULL, 'E'},
{"locale", required_argument, NULL, },
{"lc-collate", required_argument, NULL, },
{"lc-ctype", required_argument, NULL, },
{"lc-monetary", required_argument, NULL, },
{"lc-numeric", required_argument, NULL, },
{"lc-time", required_argument, NULL, },
{"lc-messages", required_argument, NULL, },
{"no-locale", no_argument, NULL, },
{"text-search-config", required_argument, NULL, 'T'},
{"auth", required_argument, NULL, 'A'},
{"pwprompt", no_argument, NULL, 'W'},
{"pwfile", required_argument, NULL, },
{"username", required_argument, NULL, 'U'},
{"help", no_argument, NULL, '?'},
{"version", no_argument, NULL, 'V'},
{"debug", no_argument, NULL, 'd'},
{"show", no_argument, NULL, 's'},
{"noclean", no_argument, NULL, 'n'},
{"xlogdir", required_argument, NULL, 'X'},
{NULL, , NULL, }
}; int c,i,ret;
int option_index;
char *effective_user;
char *pgdenv; /* PGDATA value gotten from and sent to
* environment */
char bin_dir[MAXPGPATH];
char *pg_data_native;
int user_enc; #ifdef WIN32
char *restrict_env;
#endif
static const char *subdirs[] = {
"global",
"pg_xlog",
"pg_xlog/archive_status",
"pg_clog",
"pg_notify",
"pg_serial",
"pg_subtrans",
"pg_twophase",
"pg_multixact/members",
"pg_multixact/offsets",
"base",
"base/1",
"pg_tblspc",
"pg_stat_tmp"
}; progname = get_progname(argv[]); set_pglocale_pgservice(argv[], PG_TEXTDOMAIN("initdb"));
......
}
上述程序部分运行后，get_progname的返回值是：
progname ----------initdb
而我传递给 get_progname的参数 argv[0] 是 : /home/pgsql/project/bin/initdb
再来看 set_pglocale_pgservice函数：
此时传递的第一个参数是： /home/pgsql/project/bin/initdb 传递的第二个参数是：initdb-9.1
由于 set_pglocale_pgservice 也会被postgres进程所调用，所以需要第二个参数来明确调用者。
/*
* set_pglocale_pgservice
*
* Set application-specific locale and service directory
*
* This function takes the value of argv[0] rather than a full path.
*
* (You may be wondering why this is in exec.c. It requires this module's
* services and doesn't introduce any new dependencies, so this seems as
* good as anyplace.)
*/
void
set_pglocale_pgservice(const char *argv0, const char *app)
{
char path[MAXPGPATH];
char my_exec_path[MAXPGPATH];
char env_path[MAXPGPATH + sizeof("PGSYSCONFDIR=")]; /* longer than
* PGLOCALEDIR */
/* don't set LC_ALL in the backend */
if (strcmp(app, PG_TEXTDOMAIN("postgres")) != )
setlocale(LC_ALL, ""); if (find_my_exec(argv0, my_exec_path) < )
return;
#ifdef ENABLE_NLS
get_locale_path(my_exec_path, path);
bindtextdomain(app, path);
textdomain(app); if (getenv("PGLOCALEDIR") == NULL)
{
/* set for libpq to use */
snprintf(env_path, sizeof(env_path), "PGLOCALEDIR=%s", path);
canonicalize_path(env_path + );
putenv(strdup(env_path));
}
#endif if (getenv("PGSYSCONFDIR") == NULL)
{ get_etc_path(my_exec_path, path); /* set for libpq to use */
snprintf(env_path, sizeof(env_path), "PGSYSCONFDIR=%s", path);
canonicalize_path(env_path + );
putenv(strdup(env_path)); }
}
实际上，运行时，得到的
my_exec_path : /home/pgsql/project/bin/initdb
env_path : PGSYSCONFDIR=/home/pgsql/project/etc