#Clarify vs verify code

In all other cases, Verify macros will evaluate their expressions, but will not halt execution or output text to the log. Defining USE_CHECKS_IN_SHIPPING to hold a true value, generally 1, overrides this behavior.

Verify macros operate fully in Debug, Development, Test, and Shipping Editor builds, except those ending in 'Slow', which only operate in Debug builds. Check, however, will simply not call the function at all in shipping builds, resulting in different behavior.

This is because, in shipping builds, Verify will ignore the return value, but will still perform the action. For example, if you have a function that performs an action and then returns a bool indicating whether that action succeeded or failed, you should use Verify rather than Check to make sure that the action was successful. This means that you should use Verify macros only when the expression needs to run independently of diagnostic checks. However, Verify macros evaluate their expressions even in builds where Check macros are disabled. The Verify family behaves identically to the Check family in most builds. Projects should ship with USE_CHECKS_IN_SHIPPING set to its default value of 0.

#Clarify vs verify code

This can be useful if you suspect that code inside a Check macro is altering a value, or you have Shipping-only bugs that are hard to track down, and that you suspect would be caught by your existing Check macros. Defining USE_CHECKS_IN_SHIPPING to hold a true value (generally 1), makes Check macros operate in all builds. Halts execution if the line is ever hit, similar to check(false), but intended for virtual functions that should be overridden and not calledĬheck macros operate in Debug, Development, Test, and Shipping Editor builds, except those ending in 'Slow', which only operate in Debug builds. Halts execution if the line is hit more than once without leaving scope Halts execution if the line is hit more than once Halts execution if the line is ever hit, similar to check(false), but intended for code paths that should be unreachable Halts execution if Expression is false and outputs FormattedText to the logĮxecutes Code within a do-while loop structure that runs once primarily useful as a way to prepare information that another Check requires The following Check macros are available: The Check family is the closest to the base assert, in that members of this family halt execution when the first parameter evaluates to a false value, and do not run in shipping builds by default. Each one behaves slightly differently, but they all serve the same general role as diagnostic tools for use during development. If you would like to examine the code behind these features, you can find the relevant macros in Engine/Source/Runtime/Core/Public/Misc/AssertionMacros.h. Unreal Engine 4 (UE4) provides three different families of assert equivalents: check, verify, and ensure. The simplest way to think of assert is that whatever is 'asserted' must be true, or the program will stop running. A key feature of assert is that it doesn't exist in shipping code, meaning it has no performance impact on a shipped product, but also must not have any side effects. In some cases, assert discovers bugs that cause delayed crashes before the actual crash happens, such as deleting an object that will be required in a future tick, assisting the developer at discovering the root cause of an eventual crash. These conditions are often checks that a pointer is non-null, a divisor is non-zero, a function isn't running recursively, or other important assumptions that the code requires, but that would be inefficient to check every time. In C and C++ programming, assert helps to detect and diagnose unexpected or invalid runtime conditions during development.