How To Debug Bus Error
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code with the -g option. This tells the compiler to annotate your executtable with the names of variables, locations in the code etc. Then type gdb. At the prompt type file nameOfExecutable. Then use the set command to bus error c++ set any parameters that you would type after the executable. For example if you would normally bus error linux type fred arg1 arg2 then you can do: gdb file [filename] set args [arg1] [arg2] r or gdb [filename] run arg1 arg2 The r command bus error (core dumped) linux will run the debugger. When it gets the bus error, seg fault or whatever, the location in your source code will be displayed. If you want to see the whole stack to help find out where the failing routine was how to solve bus error in linux called from etc you can use the bt command which backtraces the execution stack. quit gets you out of the debugger. Go to the gnu documention on the web for details or just type help in gdb. The Man Page for gdb Here is the man page for gdb. As you can see it can do a lot more than just the tiny example above. GNU Tools gdb(1) NAME gdb - The GNU Debugger SYNOPSIS gdb [-help] [-nx] [-q] [-batch] [-cd=dir]
Bus Error Vs Segmentation Fault
[-f] [-b bps] [-tty=dev] [-s symfile] [-e prog] [-se prog] [-c core] [-x cmds] [-d dir] [prog[core|procID]] DESCRIPTION The purpose of a debugger such as GDB is to allow you to see what is going on ``inside'' another program while it executes-or what another program was doing at the moment it crashed. GDB can do four main kinds of things (plus other things in support of these) to help you catch bugs in the act: o Start your program, specifying anything that might affect its behavior. o Make your program stop on specified conditions. o Examine what has happened, when your program has stopped. o Change things in your program, so you can experiment with correcting the effects of one bug and go on to learn about another. You can use GDB to debug programs written in C, C++, and Modula-2. Fortran support will be added when a GNU Fortran compiler is ready. GDB is invoked with the shell command gdb. Once started, it reads commands from the terminal until you tell it to exit with the GDB command quit. You can get online help from gdb itself by using the command help. You can run gdb with no arguments or options; but the most usual way to start GDB is with one argument or two, specify- ing an executable program as the argument: gdb program You can also start with both an executable program and a core file specified: GNU Tools Last change:
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Bus Error Core Dumped C
Us Learn more about Stack Overflow the company Business Learn more about hiring bus error 10 mac developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the bus error (core dumped) centos Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up What is a bus error? up http://marvin.cs.uidaho.edu/Teaching/CS445/gdb.html vote 156 down vote favorite 49 What does the "bus error" message mean, and how does it differ from a segfault? c unix segmentation-fault bus-error share|improve this question edited Oct 18 '15 at 10:44 Cool Guy 15.7k51952 asked Oct 17 '08 at 14:48 raldi 7,257216178 add a comment| 15 Answers 15 active oldest votes up vote 151 down vote accepted Bus errors are rare nowadays on x86 http://stackoverflow.com/questions/212466/what-is-a-bus-error and occur when your processor cannot even attempt the memory access requested, typically: using a processor instruction with an address that does not satisfy its alignment requirements. Segmentation faults occur when accessing memory which does not belong to your process, they are very common and are typically the result of: using a pointer to something that was deallocated. using an uninitialized hence bogus pointer. using a null pointer. overflowing a buffer. PS: To be more precise this is not manipulating the pointer itself that will cause issues, it's accessing the memory it points to (dereferencing). share|improve this answer edited Oct 17 '08 at 15:18 answered Oct 17 '08 at 15:12 bltxd 5,72322336 52 They aren't rare; I'm just at Exercise 9 from How to Learn C the Hard Way and already encountered one... –11684 Mar 26 '13 at 20:12 5 Another cause of bus errors (on Linux anyway) is when the operating system can't back a virtual page with physical memory (e.g. low-memory conditions or out of huge pages when using huge page memory.) Typically mmap (and malloc) just reserve the virtual address space, and the kernel assigns the physical memory on demand (so calle
challenged and removed. (July 2015) (Learn how and when to remove this template message) In computing, a bus error is a fault raised by hardware, notifying an operating system (OS) that https://en.wikipedia.org/wiki/Bus_error a process is trying to access memory that the CPU cannot physically address: an invalid address for the address bus, hence the name. In modern use on most architectures these are much rarer than segmentation faults, which occur primarily due to memory access violations: problems in the logical address or permissions. On POSIX-compliant platforms, bus errors usually result in the SIGBUS signal being bus error sent to the process that caused the error. SIGBUS can also be caused by any general device fault that the computer detects, though a bus error rarely means that the computer hardware is physically broken—it is normally caused by a bug in a program's source code.[citation needed] Bus errors may also be raised for certain other paging errors; see below. Contents 1 Causes 1.1 bus error (core Non-existent address 1.2 Unaligned access 1.3 Paging errors 2 Example 3 References Causes[edit] There are at least three main causes of bus errors: Non-existent address[edit] Software instructs the CPU to read or write a specific physical memory address. Accordingly, the CPU sets this physical address on its address bus and requests all other hardware connected to the CPU to respond with the results, if they answer for this specific address. If no other hardware responds, the CPU raises an exception, stating that the requested physical address is unrecognized by the whole computer system. Note that this only covers physical memory addresses. Trying to access an undefined virtual memory address is generally considered to be a segmentation fault rather than a bus error, though if the MMU is separate, the processor can't tell the difference. Unaligned access[edit] Most CPUs are byte-addressable, where each unique memory address refers to an 8-bit byte. Most CPUs can access individual bytes from each memory address, but they generally cannot access larger units (16 bits, 32 bits, 64 bits and so on) without these units being "aligned" to a specific boundary (the x86 p