system call

noun

UK /ˈsɪstəm kɔːl/

US /ˈsɪstəm kɔːl/

A way for a computer program to ask the computer's brain to do something for it.

The program used a system call to read the file from the disk.

SYNONYMS

syscall kernel call service call supervisor call

RELATED WORDS

operating system kernel API interrupt library function

OTHER MEANINGS

2. In computing, the specific instruction or mechanism that switches a processor from user mode to kernel mode.

The trap instruction triggered the system call entry point.

3. A request made by an application to the operating system for a privileged operation such as file access or process creation.

Creating a new process requires a system call like fork.

4. The interface layer that lets user programs use hardware and OS services without direct access to them.

Programmers often wrap system calls in standard library functions.