On some Unix-like

Unix-like

A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....

 platforms, SIGEMT 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 computer program

Computer program

A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...

s when an emulator

Emulator

In computing, an emulator is hardware or software or both that duplicates the functions of a first computer system in a different second computer system, so that the behavior of the second system closely resembles the behavior of the first system...

 trap occurs. 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 SIGEMT is defined in signal.h. Symbolic signal names are used because signal numbers can vary across platforms.

Etymology

SIG is a common prefix for signal names. EMT is an abbreviation

Abbreviation

An abbreviation is a shortened form of a word or phrase. Usually, but not always, it consists of a letter or group of letters taken from the word or phrase...

 for emulator trap; it is the name of an instruction on the highly influential PDP-11

PDP-11

The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...

 architecture.

Usage

On the PDP-11 architecture, EMT, TRAP, BPT and IOT were instructions used for program traps. EMT was for system software, TRAP for programmer use, BPT for debugging

Debugging

Debugging is a methodical process of finding and reducing the number of bugs, or defects, in a computer program or a piece of electronic hardware, thus making it behave as expected. Debugging tends to be harder when various subsystems are tightly coupled, as changes in one may cause bugs to emerge...

, and IOT for I/O

Input/output

In computing, input/output, or I/O, refers to the communication between an information processing system , and the outside world, possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it...

 routines. Currently EMT does not have a standardised usage.

Solaris

Solaris Operating System

Solaris is a Unix operating system originally developed by Sun Microsystems. It superseded their earlier SunOS in 1993. Oracle Solaris, as it is now known, has been owned by Oracle Corporation since Oracle's acquisition of Sun in January 2010....

 sends SIGEMT to new lightweight processes to enable them to reset hardware performance counters.

In LynxOS

LynxOS

The LynxOS RTOS is a Unix-like real-time operating system from LynuxWorks . Sometimes known as the Lynx Operating System, LynxOS features full POSIX conformance and, more recently, Linux compatibility...

, SIGEMT is an alias of the SIGCORE signal, used to kill the process with a core dump

Core dump

In computing, a core dump consists of the recorded state of the working memory of a computer program at a specific time, generally when the program has terminated abnormally...

.