Watch (computer programming)

In software development, a breakpoint is an intentional stopping or pausing place in a program, put in place for debugging purposes. It is also sometimes simply referred to as a pause.

More generally, a breakpoint is a means of acquiring knowledge about a program during its execution. During the interruption, the programmer inspects the test environment (general purpose registers, memory, logs, files, etc.) to find out whether the program is functioning as expected. In practice, a breakpoint consists of one or more conditions that determine when a program's execution should be interrupted.

Breakpoints are most commonly used to interrupt a running program immediately before the execution of a programmer-specified instruction. This is often referred to as an instruction breakpoint.

Other kinds of conditions can also be used, such as the reading, writing, or modification of a specific location in an area of memory. This is often referred to as a conditional breakpoint, a data breakpoint, or a watchpoint.

Breakpoints can also be used to interrupt execution at a particular time, upon a keystroke etc.

When a breakpoint is hit, various tools are used to inspect the state of the program or alter it. Stack trace of each thread may be used to see the chain of function calls that led to the paused instruction. A list of watches allows one to view the values of selected variables and expressions. There may also be tools to show the contents of registers, loaded program modules and other information.

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