请教CLIENTFUNC是什么意思啊

tecson

 

int

ads_new_dialog(

const char * dlgname,

int dcl_id,

CLIENTFUNC def_callback,

ads_hdlg * hdlg);

dlgname	Description to come
dcl_id	Description to come
def_callback	Description to come
hdlg	Description to come

帮助文件中没找到CLIENTFUNC的解释，能帮忙解释一下吗