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To expose dangling pointer errors, one common programming technique is to set pointers to the null pointer or to an invalid address once the storage they point to has been released. When the null pointer is dereferenced (in most languages) the program will immediately terminate—there is no potential for data corruption or unpredictable behavior.
In computer science, a tagged pointer is a pointer (concretely a memory address) with additional data associated with it, such as an indirection bit or reference count.This additional data is often "folded" into the pointer, meaning stored inline in the data representing the address, taking advantage of certain properties of memory addressing.
Pointers also must have an associated type and a pointer to one type is not compatible with a pointer to another type (e.g. a pointer to a char is not compatible with a pointer to an integer). This helps eliminate the type security issues inherent with other pointer implementations, particularly those used for PL/I or C .
Many instances of the most commonly used garbage-collected type, the string, have a short lifetime, since they are typically intermediate values in string manipulation. A lot of local string usage could be optimized away, but the compiler currently doesn't do it. The reference count of a string is checked before mutating a string.
On many common platforms, this use of pointer punning can create problems if different pointers are aligned in machine-specific ways. Furthermore, pointers of different sizes can alias accesses to the same memory, causing problems that are unchecked by the compiler. Even when data size and pointer representation match, however, compilers can ...
An example for which a conservative garbage collector would be needed is the C language, which allows typed (non-void) pointers to be type cast into untyped (void) pointers, and vice versa. A related issue concerns internal pointers, or pointers to fields within an object. If the semantics of a language allow internal pointers, then there may ...
A value or pointer to other data may be associated with every node in the tree, or sometimes only with the leaf nodes, which have no children nodes. The abstract data type (ADT) can be represented in a number of ways, including a list of parents with pointers to children, a list of children with pointers to parents, or a list of nodes and a ...
In computer science, pointer analysis, or points-to analysis, is a static code analysis technique that establishes which pointers, or heap references, can point to which variables, or storage locations. It is often a component of more complex analyses such as escape analysis. A closely related technique is shape analysis.