继续分析：

setup_conversion();

展开：

其实质是：

运行命令："/home/pgsql/project/bin/postgres" --single -F -O -c search_path=pg_catalog -c exit_on_error=true template1 >/dev/null

传递参数：/home/pgsql/project/share/conversion_create.sql

/* * load conversion functions */static voidsetup_conversion(void){    PG_CMD_DECL;    char      **line;    char      **conv_lines;    fputs(_("creating conversions ... "), stdout);    fflush(stdout);    snprintf(cmd, sizeof(cmd),             "\"%s\" %s template1 >%s",             backend_exec, backend_options,             DEVNULL);    PG_CMD_OPEN;    conv_lines = readfile(conversion_file);    for (line = conv_lines; *line != NULL; line++)    {        if (strstr(*line, "DROP CONVERSION") != *line)            PG_CMD_PUTS(*line);        free(*line);    }    free(conv_lines);    PG_CMD_CLOSE;    check_ok();}