In operating systems , a system call , also known as a system service request , is the mechanism an application uses to request service from the operating system ' s kernel 在操作系統(tǒng)中,系統(tǒng)調(diào)用,也稱為系統(tǒng)服務(wù)請求,是應(yīng)用程序用來向操作系統(tǒng)內(nèi)核請求服務(wù)的一種機制。