SIGTSTP is a signal in a Unix computer system that tells a program to stop temporarily. On POSIX

POSIX

POSIX , an acronym for "Portable Operating System Interface", is a family of standards specified by the IEEE for maintaining compatibility between operating systems...

-compliant platforms, SIGTSTP is the signal

Signal (computing)

A signal is a limited form of inter-process communication used in Unix, Unix-like, and other POSIX-compliant operating systems. Essentially it is an asynchronous notification sent to a process in order to notify it of an event that occurred. When a signal is sent to a process, the operating system...

 sent to a process

Process (computing)

In computing, a process is an instance of a computer program that is being executed. It contains the program code and its current activity. Depending on the operating system , a process may be made up of multiple threads of execution that execute instructions concurrently.A computer program is a...

 by its controlling terminal when the user requests that the process be suspended. The symbolic constant

C preprocessor

The C preprocessor is the preprocessor for the C and C++ computer programming languages. The preprocessor handles directives for source file inclusion , macro definitions , and conditional inclusion ....

 for SIGTSTP is defined in the header file

Header file

Some programming languages use header files. These files allow programmers to separate certain elements of a program's source code into reusable files. Header files commonly contain forward declarations of classes, subroutines, variables, and other identifiers...

 signal.h. Symbolic signal names are used because signal numbers can vary across platforms.

Etymology

SIG is a common prefix for signal names. TSTP is an abbreviation for tty stop, indicating that stop has been typed at the tty (the controlling terminal of the process). (Tty is itself an abbreviation for teletypewriter, an archaic type of computer terminal

Computer terminal

A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system...

.)

Usage

SIGTSTP is sent to a process by its controlling terminal when the user presses the special SUSP key combination (usually control-Z

Control-Z

In computing, is a control character in ASCII code, also known as the substitute character or a keyboard shortcut. Strictly speaking, is not a printable character at all but a code for control purposes, though it is sometimes rendered by two characters as ^Z. It is generated by pressing the key...

). By default, SIGTSTP causes the process receiving it to stop until a SIGCONT

SIGCONT

On POSIX-compliant platforms, SIGCONT is the signal sent to restart a process previously paused by the SIGSTOP or SIGTSTP signal. The symbolic constant for SIGCONT is defined in the header file signal.h. Symbolic signal names are used because signal numbers can vary across platforms.-Etymology:SIG...

 signal is received. Unlike the similar SIGSTOP

SIGSTOP

On POSIX-compliant platforms, SIGSTOP is the signal sent to a process to stop it for later resumption. The symbolic constant for SIGSTOP is defined in the header file signal.h. Symbolic signal names are used because signal numbers can vary across platforms....

signal, a process can register a signal handler for or ignore SIGTSTP.