For 2023 (and 2024 ...) - we are now fully retired from IT training. We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.
Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!
I am also active in many other area and still look after a lot of web sites - you can find an index ((here)) |
Segmentation Fault, Segmentation Violation, Bus Error, Stack Smashing
Have you ever had these error messages come up from your C program and wondered what they really mean?
Segmentation Fault
Segmentation Violation
Bus Error
stack smashing detected
A segmentation fault is when you try to access memory that doesn't exits. A segmentation violation is when you try to access memory that's not your process's. A bus error is when you try to an address that points to the memory bus. Stack Smashing is when you try to reduce the stack to less than zero in size.
But they really all mean the same thing - you've made a mistake with your addresses and pointers, called a function (in K & R C) with the wrong number of parameters (or got a wrong function prototype in ANSI C), or you've overrun an array and corrupted something.
A great deal of moving from being a new C and C++ programmer to an efficient and experienced one is about knowing how to naturally avoid messages like these in the first place, and about learning how to quickly spot the cause when they do occur.
Can I make a strong recommendation? Write your code in named blocks - functions or methods, build test programs for those named blocks, keep your tests so you can run and rerun them. You won't eliminate the segmentation, stack and bus errors - but you will help yourself find them in a relatively small area of code. Informally, I'm recommending that you move towards test driven, or behaviour driven, development! (written 2014-12-04, updated 2014-12-03)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles C208 - C and C based languages - Programming techniques and tools [4336] Test Driven Development - a first example of principle in C - (2014-12-01) C050 - C and C based languages - C - General [2002] New C Examples - pointers, realloc, structs and more - (2009-01-20) [2086] C Programming v Learning to Program in C. Which course? - (2009-03-17) [2091] C, C++ and C# ... Java and JavaScript - (2009-03-20) [2504] Learning to program in ... - (2009-11-15) [2536] All the Cs ... and Java too - (2009-12-13) [2669] Efficient use of dynamic memory - C and realloc - (2010-03-10) [2763] Our C and C++ training course are on Open Source platforms - (2010-05-13) [2848] C course - final course example puts it all together - (2010-07-02) [3053] Make - automating the commands for building and installing - (2010-11-16) [3129] Extra courses - C and C++ - (2011-01-12) [4335] Flexible public courses - residential or commuting, programming newcomer or experienced, C or C++ - (2014-11-30) [4434] Public training courses - upcoming dates - (2015-02-21)
Some other Articles
Incrementing a variable in Java - Pre and Post IncrementPython base and inherited classes, test harness and unit testing - new examplesPolitics and the railway the connects WiltshireMy first official measure - Passenger Entrys and Exits - revisited 9 years laterSegmentation Fault, Segmentation Violation, Bus Error, Stack Smashing Command line and file handling in CSimple C structs - building up to full, dynamic examplePassing arrays into functions in CLearning to program sample program - past its prime, but still useful
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This is a page archived from The Horse's Mouth at
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