Back Falla de segmentació Catalan Porušení ochrany paměti Czech Schutzverletzung German Violación de acceso Spanish Muistialueen ylitys Finnish Erreur de segmentation French שגיאת סגמנטציה HE Errore di segmentazione Italian セグメンテーション違反 Japanese 세그멘테이션 오류 Korean
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In computing, a segmentation fault (often shortened to segfault) or access violation is a fault, or failure condition, raised by hardware with memory protection, notifying an operating system (OS) the software has attempted to access a restricted area of memory (a memory access violation). On standard x86 computers, this is a form of general protection fault. The operating system kernel will, in response, usually perform some corrective action, generally passing the fault on to the offending process by sending the process a signal. Processes can in some cases install a custom signal handler, allowing them to recover on their own,[1] but otherwise the OS default signal handler is used, generally causing abnormal termination of the process (a program crash), and sometimes a core dump.
Segmentation faults are a common class of error in programs written in languages like C that provide low-level memory access and few to no safety checks. They arise primarily due to errors in use of pointers for virtual memory addressing, particularly illegal access. Another type of memory access error is a bus error, which also has various causes, but is today much rarer; these occur primarily due to incorrect physical memory addressing, or due to misaligned memory access – these are memory references that the hardware cannot address, rather than references that a process is not allowed to address.
Many programming languages have mechanisms designed to avoid segmentation faults and improve memory safety. For example, Rust employs an ownership-based[2] model to ensure memory safety.[3] Other languages, such as Lisp and Java, employ garbage collection,[4] which avoids certain classes of memory errors that could lead to segmentation faults.[5]
- ^ Expert C programming: deep C secrets By Peter Van der Linden, page 188
- ^ "The Rust Programming Language - Ownership".
- ^ "Fearless Concurrency with Rust - The Rust Programming Language Blog".
- ^ McCarthy, John (April 1960). "Recursive functions of symbolic expressions and their computation by machine, Part I". Communications of the ACM. 4 (3): 184–195. doi:10.1145/367177.367199. S2CID 1489409. Retrieved 2018-09-22.
- ^ Dhurjati, Dinakar; Kowshik, Sumant; Adve, Vikram; Lattner, Chris (1 January 2003). "Memory safety without runtime checks or garbage collection" (PDF). Proceedings of the 2003 ACM SIGPLAN conference on Language, compiler, and tool for embedded systems. Vol. 38. ACM. pp. 69–80. doi:10.1145/780732.780743. ISBN 1581136471. S2CID 1459540. Retrieved 2018-09-22.