Search results
Results from the WOW.Com Content Network
Type errors (such as an attempt to apply the ++ increment operator to a Boolean variable in Java) and undeclared variable errors are sometimes considered to be syntax errors when they are detected at compile-time. It is common to classify such errors as (static) semantic errors instead. [2] [3] [4]
The development of these languages involved a design philosophy in which conflicts between performance and safety were generally resolved in favor of performance. The programmer was given the burden of being aware of dangerous issues such as uninitialized variables. In other languages, variables are often initialized to known values when created.
This can result in bugs that are exposed when a different compiler, or different settings, are used. Testing or fuzzing with dynamic undefined behavior checks enabled, e.g., the Clang sanitizers, can help to catch undefined behavior not diagnosed by the compiler or static analyzers. [5] Undefined behavior can lead to security vulnerabilities in ...
An undefined variable in the source code of a computer program is a variable that is accessed in the code but has not been declared by that code. [1] In some programming languages, an implicit declaration is provided the first time such a variable is encountered at compile time. In other languages such a usage is considered to be sufficiently ...
This is an accepted version of this page This is the latest accepted revision, reviewed on 9 January 2025. Look up undefined in Wiktionary, the free dictionary. Undefined may refer to: Mathematics Undefined (mathematics), with several related meanings Indeterminate form, in calculus Computing Undefined behavior, computer code whose behavior is not specified under certain conditions Undefined ...
An undefined value must not be confused with empty string, Boolean "false" or other "empty" (but defined) values. Depending on circumstances, evaluation to an undefined value may lead to exception or undefined behaviour, but in some programming languages undefined values can occur during a normal, predictable course of program execution.
This combination effectively blurs the distinction between parsing and execution, and makes syntax analysis an undecidable problem in these languages, meaning that the parsing phase may not finish. For example, in Perl it is possible to execute code during parsing using a BEGIN statement, and Perl function prototypes may alter the syntactic ...
In mathematics, the term undefined refers to a value, function, or other expression that cannot be assigned a meaning within a specific formal system. [ 1 ] Attempting to assign or use an undefined value within a particular formal system, may produce contradictory or meaningless results within that system.