Bah - I can crash C in 5 characters:

main;

This declares an implicit int variable called main . It s global so the variable has an initial value of 0. It s C the names aren t decorated - so the linker doesn t realize that it s a var and not a function.

GCC gave me a warning - but that s all.

$ gcc crash.c 
crash.c:1: warning: data definition has no type or storage class
$ ./a.exe
Segmentation fault (core dumped)
$

Crash with 0 characters:

$ > golf.c
$ gcc -Wl,--defsym=main=0 golf.c
$ ./a.out
Segmentation fault

I wonder if this counts...

a

This is in JavaScript. This gives the runtime error of "object not found". Since JavaScript is a dynamic language, syntactically this is actually correct. Still feels like twisting the rules. :P

using python:

1/0

X86 machine code: 1 byte

From cmd prompt in windows create file a.com containing byte F4, x86 halt instruction:

F:>debug
-a 100
0BFD:0100 hlt
0BFD:0101
-r cx
CX 0000
:1
-n a.com
-w
Writing 00001 bytes
-q

F:>a.com

The NTVDM CPU has encountered illegal instruction

$ cat > crash.S
hlt
$ as -o crash.o crash.S
$ ld crash.o
ld: warning: cannot find entry symbol _start; defaulting to 0000000008048054
$ ./a.out
Segmentation fault

Perl

die

Died at test line 1.

die

prints the value of LIST to STDERR and exits with the current value of $! (errno).

Commodore 64 BASIC:

poke 2,2:sys2

or shorter (using PETSCII graphic-char shortcuts):

pO2,2:sY2

(crash: $02 invalid opcode on MOS/CSG6510). Actually it can be done in 7 bytes (3-instructions):

lda #$02
sta $02
jmp $0002

If you re at a computer store that has TI-89s, you can crash one by typing this in:

Exec "00000000"

(that s 8 zeros)

It will yield "Illegal Instruction". Press 2nd+Left+Right+ON to reset the calc.

If you want to have more fun, do this:

Exec "4E4A4E750000"

That launches the hidden hardware test menu, including memory tests, LCD tests (draws checkerboards et al.) and more. Unfortunately, the status bar gets erased, and nothing in the calc s OS draws it back, so to clean up after yourself, reset per the instructions above, or do this:

Exec "307C56E670FF20C020C020C020C020C04E750000"

Brainf*ck

5 characters

+[>+]

It will take it a while, but eventually the program will run out of memory and inevitably crash.

Factor (or Forth)

.

"Data stack underflow"

How about java Z? If no file exists it will "crash" with a java.lang.NoClassDefFoundError. So my answer is zero letters. If that is not valid then...

class T{}

Would "crash" with $ java T Exception in thread "main" java.lang.NoSuchMethodError: main

If you want something that actually runs, then if you are willing to abuse things a little

class T{static {int i =1/0;}}

Else

class T{public static void main(String[]a){main(a);}}

to quote this answer:

All these answers and no Befunge? I d wager a fair amount it s shortest solution of them all:

1

Not kidding. Try it yourself: http://www.quirkster.com/js/befunge.html

EDIT: I guess I need to explain this one. The 1 operand pushes a 1 onto Befunge s internal stack and the lack of anything else puts it in a loop under the rules of the language.

Using the interpreter provided, you will eventually--and I mean eventually--hit a point where the Javascript array that represents the Befunge stack becomes too large for the browser to reallocate. If you had a simple Befunge interpreter with a smaller and bounded stack--as is the case with most of the languages below--this program would cause a more noticeable overflow faster.

In C, 20 characters:

void main(){main();}

Update: Suggested by roe, 15 characters:

main(){main();}

Note: Tested with VC++ 2008.

Late, but whatever. PHP, 32 characters.

$r=function($z){$z($z);};$r($r);

gives Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 261900 bytes) in ...

Technically, I could also do it in 29 with

$r=function($z){$z();};$r(0);

But that isn t as much fun as infinite recursion. That, and I don t think "undefined function" errors should count as "compiling" in a scripting language, otherwise:

Z();

would be the smallest solution.

Also, instead of crashing, how about (as a script) surpassing max execution time? 8 chars:

for(;;);

My original take on that had a $i++ in the third expression of the for loop, but because PHP treats all integers as signed, instead of overflowing, it just goes negative.

Try this in assembly:

push 0
ret

of course add the all other garbage to compile into an application.

in windows powershell:

throw

Perl in only 2 chars.

&a

Undefined subroutine &main::a called at test.pl line 1.

Scheme:

(1)

Filler text to make this longer.

In QBasic:

? 1/0

(At least I think it ll still compile and then crash with divide-by-zero; it s been quite some time...)

In C, 33 characters:

int main(void){return*((int*)0);}

Golfscript - 1 Char

Lots of operators can do it, eg

*

(eval):1:in `initialize : undefined method `class_id  for nil:NilClass (NoMethodError)
from ../golfscript.rb:285:in `call 
from ../golfscript.rb:285:in `go 
from (eval):1:in `initialize 
from ../golfscript.rb:285:in `call 
from ../golfscript.rb:285:in `go 
from ../golfscript.rb:477

main = undefined

In Haskell.

F# 3 characters

1/0

Does compile, though gives a warning.

Lua, 3 characters

The divide by zero does not cause problems in Lua, but here something just as short:

a()

gives:

lua: isort.lua:1: attempt to call global  a  (a nil value)
stack traceback:
    a.lua:1: in main chunk
    [C]: ?

F#, 11 characters

box 0 :?> unit

Compiles without a warning. Crashes with: System.InvalidCastException: Unable to cast object of type System.Int32 to type Microsoft.FSharp.Core.Unit .

PostScript, 1 character

Like GolfScript:

*

Syntactically legal, but crashes during runtime because the token * is not defined (different reason than why GolfScript crashes).

int main () { int n = 0; return 1 / n; }

It depends upon the allowed max stack size for a thread. But it does crash when compiled using VC9:

int main()
{
    int a[10000000];
    return 0;
};

Perl

3 characters

1/0

Produces:

Illegal division by zero at crash.pl line 1.

(still looking for something that will do it in two..)