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Things to commit just before leaving your job
// Just before switching jobs:
// Add one of these.
// Preferably into the same commit where you do a large merge.
//
// This started as a tweet with a joke of "C++ pro-tip: #define private public",
// and then it quickly escalated into more and more evil suggestions.
// I've tried to capture interesting suggestions here.
//
// Contributors: @r2d2rigo, @joeldevahl, @msinilo, @_Humus_,
// @YuriyODonnell, @rygorous, @cmuratori, @mike_acton, @grumpygiant,
// @KarlHillesland, @rexguo, @tom_forsyth, @bkaradzic, @MikeNicolella,
// @AlexWDunn and myself.
//
// In case it's not clear: I am not suggesting you *actually* do this!
// Easy keyword replacement. Too easy to detect I think!
#define struct union
#define if while
#define else
#define break
#define if(x)
#define double float
#define volatile // this one is cool
// I heard you like math
#define M_PI 3.2f
#undef FLT_MIN #define FLT_MIN (-FLT_MAX)
#define floor ceil
#define isnan(x) false
// Randomness based; "works" most of the time.
#define true ((__LINE__&15)!=15)
#define true ((rand()&15)!=15)
#define if(x) if ((x) && (rand() < RAND_MAX * 0.99))
// String/memory handling, probably can live undetected quite long!
#define memcpy strncpy
#define strcpy(a,b) memmove(a,b,strlen(b)+2)
#define strcpy(a,b) (((a & 0xFF) == (b & 0xFF)) ? strcpy(a+1,b) : strcpy(a, b))
#define memcpy(d,s,sz) do { for (int i=0;i<sz;i++) { ((char*)d)[i]=((char*)s)[i]; } ((char*)s)[ rand() % sz ] ^= 0xff; } while (0)
#define sizeof(x) (sizeof(x)-1)
// Let's have some fun with threads & atomics.
#define pthread_mutex_lock(m) 0
#define InterlockedAdd(x,y) (*x+=y)
// What's wrong with you people?!
#define __dcbt __dcbz // for PowerPC platforms
#define __dcbt __dcbf // for PowerPC platforms
#define __builtin_expect(a,b) b // for gcc
#define continue if (HANDLE h = OpenProcess(PROCESS_TERMINATE, false, rand()) ) { TerminateProcess(h, 0); CloseHandle(h); } break
// Some for HLSL shaders:
#define row_major column_major
#define nointerpolation
#define branch flatten
#define any all
@nickiannone

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nickiannone commented Aug 13, 2013

This file is pure evil.

@frkn

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frkn commented Aug 13, 2013

Commits by Satan

@CTrauma

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CTrauma commented Aug 13, 2013

MY EYES!! MY EYES!! THEY BURN!!! Never thought I would actually see Snow Crash.. I was wrong..

@gkaindl

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gkaindl commented Aug 13, 2013

can I please have "#define struct union" on a t-shirt?

@TurkerTunali

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TurkerTunali commented Aug 13, 2013

define yourself

@rlabrecque

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rlabrecque commented Aug 13, 2013

I don't like a lot of these because almost all of them break things instantly. You need something that breaks things in a seemingly random fashion. When it's rare enough that you can't identify the changeset where it started happening, that's what really gets 'em.

@bkaradzic

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bkaradzic commented Aug 14, 2013

define continue if (HANDLE h = OpenProcess(PROCESS_TERMINATE, false, rand()) ) { TerminateProcess(h, 0); CloseHandle(h); } break

@ShadowIce

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ShadowIce commented Aug 14, 2013

Still one of my favorites:

define EnterCriticalSection(p) ((void)0)

define LeaveCriticalSection(p) ((void)0)

(from http://blogs.msdn.com/b/oldnewthing/archive/2013/02/26/10396960.aspx)

@brianchasalow

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brianchasalow commented Aug 14, 2013

i love this so much.

@JulianSchmid

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JulianSchmid commented Aug 15, 2013

Dear god

define true ((rand()&15)!=15)

define if(x) if ((x) && (rand() < RAND_MAX * 0.99))

this would drive me insane

@windytan

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windytan commented Aug 15, 2013

Pure genius!

@KevinKnight

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KevinKnight commented Aug 15, 2013

I think this adequately sums our feelings up: http://i1.kym-cdn.com/entries/icons/original/000/012/367/evilest.gif

@synther

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synther commented Aug 15, 2013

// Randomness based; "works" most of the time.
#define true ((__LINE__&15)!=15)
#define true ((rand()&15)!=15)
#define if(x) if ((x) && (rand() < RAND_MAX * 0.99))

is the best part!

@chenyukang

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chenyukang commented Aug 15, 2013

funny ..

@aespinoza

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aespinoza commented Aug 15, 2013

This is EVIL!

@jaharkes

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jaharkes commented Aug 15, 2013

define memcpy strncpy

@infogulch

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infogulch commented Aug 15, 2013

@rlabrecque: Fixed. Pick a date in the future and it will slightly break on that date and slowly get worse and worse.

Bonus: it won't affect performance until that date as well.

// Much cleaner version from: http://stackoverflow.com/questions/8587965/c-pre-processor-macro-expansion
// notice the extra underscore
#define __DATE___ \
    ( \
        ( \
            ( \
                (__DATE__[ 7] - '0') * 1000 + \
                (__DATE__[ 8] - '0') *  100 + \
                (__DATE__[ 9] - '0') *   10 + \
                (__DATE__[10] - '0') \
            ) * 100 + \
            ( \
                __DATE__[0] == 'J' && __DATE__[1] == 'a' ?  1 : \
                __DATE__[0] == 'F'                       ?  2 : \
                __DATE__[0] == 'M' && __DATE__[2] == 'r' ?  3 : \
                __DATE__[0] == 'A' && __DATE__[1] == 'p' ?  4 : \
                __DATE__[0] == 'M'                       ?  5 : \
                __DATE__[0] == 'J' && __DATE__[2] == 'n' ?  6 : \
                __DATE__[0] == 'J'                       ?  7 : \
                __DATE__[0] == 'A'                       ?  8 : \
                __DATE__[0] == 'S'                       ?  9 : \
                __DATE__[0] == 'O'                       ? 10 : \
                __DATE__[0] == 'N'                       ? 11 : 12 \
            ) \
        ) * 100 + \
        ( \
            ((__DATE__[4] >= '0') ? (__DATE__[4] - '0') * 10 : 0) + \
            (__DATE__[5] - '0') \
        ) \
    )

// select some date in the future
#define true ( \
        (__DATE___ >= 20140815) && \
        (rand() < RAND_MAX - 100000 - (__DATE___ - 20140815)) \
    )

// compose with others
#define if(x) if ((x) && true)

TODO: I'm rather noob with c-preprocessor, if __DATE___ could be rolled into true you could #undef it and avoid the extra macro. One way would be to just copy it twice. It's not like we're going for readable code here.

@encolpe

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encolpe commented Aug 16, 2013

in Python, a very common one:

object = None

@smb02dunnal

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smb02dunnal commented Aug 16, 2013

These could be a real pain to track down

define double float

define delete

@mrThe

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mrThe commented Aug 16, 2013

EVIL

@maximal

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maximal commented Aug 17, 2013

These could be a real pain to track down

define double float

define delete

Oh shi—

@danielbalster

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danielbalster commented Aug 19, 2013

define memset(a,b,c) memset(a,c,b) // fun to debug

@c023-DeV

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c023-DeV commented Aug 19, 2013

making list of whom never to em-ploy but rather de-ploy ... soldiers of code!

@gwihlidal

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gwihlidal commented Aug 20, 2013

define memalign(alignment, size) memalign(size, alignment)

@dronir

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dronir commented Aug 20, 2013

In Python, I'd go with

_t = True
True = False
False = _t
@blaquee

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blaquee commented Aug 20, 2013

This gist is epic.

@schrotthaufen

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schrotthaufen commented Aug 20, 2013

/* create memory leaks if compiled on April, 1st */
#define free(x) if(strncmp(__DATE__, "Apr  1", 6) != 0) free(x)
@d33tah

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d33tah commented Aug 20, 2013

I wonder what you could #define unlikely to.

@c0de517e

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c0de517e commented Aug 20, 2013

My contribution...

include

include

include

using namespace std;

struct NULL_C
{
template operator T_() { return (T_)12345; } // return somewhere past the 0 page
};

undef NULL

define NULL NULL_C()

int main()
{
cout << "Hello World" << endl;

char* x = NULL;

return *x;
}

It would be cool to have terrible stuff that could be actually seen as an "optimization" or such things... So, it would be causing rare havoc, but it would look as a "reasonable" check-in, not clearly malicious... Bad math libraries, generating NaNs... bad QLerp for example... SSE stuff would be particularly tricky... Wrong _restrict would be fun too!

Surprised noone suggested this... or maybe I missed it (probable)

include <fenv.h> // ... or equivalent... _control_fp()

fesetround(FE_TOWARDZERO);

Also:

define alignas

define attribute(aligned)

And... (VS)

pragma pack(push, 1)

Also... #define to non atomic all these http://en.cppreference.com/w/cpp/atomic

@mathiasbynens

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mathiasbynens commented Aug 21, 2013

Similar projects: evil.js and evil.css.

@trailblazr

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trailblazr commented Aug 21, 2013

How about some conditional undef's ;)

#ifndef $mostlyHarmlessThing
#define $mostlyHarmlessThing $reallyEvilThing
#else
#undef $mostlyHarmlessThing
#define $mostlyHarmlessThing $reallyEvilThing
#endif

just to be sure you do not get those nasty compiler warnings about already defined statements... hehe...

@hhsaez

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hhsaez commented Aug 21, 2013

These can cause a lot of headaches:

define unsigned

define float int

@Uristqwerty

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Uristqwerty commented Aug 22, 2013

I like the idea of "#define union struct" more than "#define struct union".

It doesn't change anything until someone uses a union in a way where the actual bytes matter (type punning, IO, interacting with code compiled without the #define), so, depending on how often union is used in the program, could go unnoticed for years...

@phucvin

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phucvin commented Aug 26, 2013

reduce performance is the most evil in game programming, so how about

define if(x) int evil##COUNTER = 10000;while(evil-- > 0);if((x))

@AnthonyAkentiev

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AnthonyAkentiev commented Aug 30, 2013

Very cool!

My favourite one:

define true ((LINE&15)!=15)

@Dracks

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Dracks commented Sep 20, 2013

Mark as bookmark! It's important to remember

define rand() 4 // It should explain Sony security problems in PS3

Thanks!

@giorakeinan

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giorakeinan commented Sep 29, 2013

For better results all the code should be wrap with #ifdef DEBUG

@silvansky

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silvansky commented Oct 11, 2013

@giorakeinan

ifndef DEBUG would be more evil =)

@mnunberg

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mnunberg commented Oct 11, 2013

#define malloc alloca
#define close dup

#define select(n, r, w, e, t) \
  usleep(__LINE__) ? select(n,r,w,e,t) : select(n,r,w,e,t)
@mnunberg

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mnunberg commented Oct 11, 2013

#define free(x) do { \
    int f__hack_v = rand(); \
    if (f__hack_v % 8) { \
        /* make it work "most" of the time */ \
        free(x); \
    } else if (f__hack_v % 4 == 0) { \
        *(char **)x += 2; \
    } else if (f__hack_v % 10 == 0) { \
        free(x); \
        free(x); \
    } else { \
        x = NULL; \
    } \
} while (0);
@mnunberg

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mnunberg commented Oct 11, 2013

/** For hard to-debug compiler issues:
#define __attribute__(x)
/** Make variadic functions break mysteriously */
#ifdef va_end
#undef va_end
#endif
#define va_end(ap)
/** Always break files */
#define fopen(p, m) fopen(p, "w")
#define fclose(p) flock(fileno(fp), LOCK_SH|LOCK_NB)
@tonkoandrew

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tonkoandrew commented Oct 12, 2013

In Python:

True, False = False, True

@Triang3l

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Triang3l commented Oct 13, 2013

// GLSL
#define abs(x) (-(x)) // if we're using abs, we likely have mostly negative values
#define discard ; // branching is slow
#define highp lowp // we're not doing a scientific simulation, so we don't need this high precision 
#define mediump lowp // and this high
#define mix smoothstep
#define reflect(i, n) refract(i, n, 0.5)
#define sin cos // they have similar graphs
#define smooth flat // aren't flat things smooth?
#define texture2D(s, p) texture2D(s, p, 2.0) // make everything blurry a little bit
@kastaneda

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kastaneda commented Nov 4, 2013

define i j

@Treewill

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Treewill commented Nov 6, 2013

#define const
@abautu

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abautu commented Feb 17, 2014

define false true

@ZehMatt

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ZehMatt commented May 1, 2014

static char __undefined_memory[1024];

define malloc(x) ((void*)__undefined_memory)

@kuzmas

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kuzmas commented Jun 26, 2014

define dynamic_cast reinterpret_cast

define return throw

@igorshapiro

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igorshapiro commented Aug 19, 2014

This one is right from gestapo dungeons... It's probably the diff between C and Objective C

@Nexuapex

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Nexuapex commented Sep 5, 2014

extern "C" __stdcall void ExitThread(unsigned long);

define InterlockedAdd64(a,b) ::rand() ? _InterlockedAdd64(a,b) : (::ExitThread(0),b)

@magic2k

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magic2k commented Dec 6, 2014

whoa

@Mechazawa

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Mechazawa commented Aug 19, 2015

#define continue break
@johnhunt

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johnhunt commented Aug 19, 2015

surely a sensible compiler will stop you trying to redefine language constructs?

@uliwitness

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uliwitness commented Aug 19, 2015

Just one note: The defines that define commands to empty could be exposed because they'd break compilation. Instead do

define break do{}while(0)

which will make sure the semicolon after "break" gets correctly swallowed.

@fjarlq

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fjarlq commented Aug 19, 2015

Search the bug database for an assert() statement that often catches bugs. For example:

assert(answer == 42);

and change it to read:

assert(answer = 42);

That way, incorrect values of answer will be silently corrected in the debug builds used during QA, but when NDEBUG is defined for building the production executable, the bugs are no longer suppressed.

(This is why I always enable the gcc -Wparentheses warning.)

@0xae

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0xae commented Aug 19, 2015

Dont know what to say!

@antoligy

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antoligy commented Aug 19, 2015

this is art

@jaw

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jaw commented Aug 19, 2015

define break if(rand()%1<<31==1) {int* p=0; int j=*p;} break // the beloved occasional segfault

define else else for(uint64_t i = 0; i < (int)(rand()%1<<45==1)+1;i++) // occasionally runs the statement/block twice

@cgranier

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cgranier commented Aug 19, 2015

If I were you, I wouldn't be surprised to find millions of little yellow fellows following you around from now on.

minions

@ElectricToy

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ElectricToy commented Aug 19, 2015

So #include <Windows.h> basically.

@ye

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ye commented Aug 19, 2015

@dronir @tonkoandrew: although it works in Python 2.7, you can't swap True and False in Python 3.4.3.

Python 2.7.10 (default, Jul 13 2015, 12:05:58) 
[GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.53)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> True, False = False, True
>>> 
Python 3.4.3 (default, Jul 13 2015, 12:18:23) 
[GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.53)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> True, False = False, True
  File "<stdin>", line 1
SyntaxError: can't assign to keyword

@encolpe your receipt for disaster still works! 😁 And the way to restore saneness is to del object 😲

Python 3.4.3 (default, Jul 13 2015, 12:18:23) 
[GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.53)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> object = None
>>> class foo(object):
...     pass
... 
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: NoneType takes no arguments
>>> del object
>>> class foo(object):
...     pass
... 
>>> f = foo()
>>> f
<__main__.foo object at 0x10ea27a90>
>>> 
@flat235

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flat235 commented Aug 19, 2015

define <= <

define >= >

Have fun with those off-by-ones

@homer242

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homer242 commented Aug 19, 2015

interesting

@arisada

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arisada commented Aug 19, 2015

define continue if(rand()%100==0) break; else continue

@alficles

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alficles commented Aug 19, 2015

#ifndef _DEBUG
#define if(x) try{int _=*(int*)0;_=_;}catch(...){}if(x)
#endif

Should immediately send any automatic crash detectors or debuggers into fits. But only in release. Of course, everything “works” properly. :D

@lnaie

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lnaie commented Aug 19, 2015

reason to be shot on sight ;)

@JessieArr

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JessieArr commented Aug 19, 2015

// Fun with off-by-one errors:
#define > >=
#define < <=
#define == <=
@joineral32

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joineral32 commented Aug 19, 2015

I added a few I thought would be funny in a fork:
https://gist.github.com/joineral32/ba144be3a696f2d25c66

@JamesBender

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JamesBender commented Aug 19, 2015

I feel like I'm going to Hell just for reading this.

@bagre

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bagre commented Aug 19, 2015

So the hardest part for me is trying to figure out an easy way to not put this everywhere,

define main(x) do(main func signature); int main(x) {SetUnhandledExceptionFilter((LPTOP_LEVEL_EXCEPTION_FILTER) exit); do(x)} int do(mainfuncsig){

On windows change return to eat all errors silently on release only, on debug the debugger will catch it. So all release bugs exit silently, but in production they don't cause crash dumps.

@zahirtezcan

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zahirtezcan commented Aug 19, 2015

Build passes! ... well ... most of the time

@tafryn

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tafryn commented Aug 19, 2015

Shouldn't these two blocks be !=0?

#define true ((__LINE__&15)!=15)
#define true ((rand()&15)!=15)
@orionnoir

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orionnoir commented Aug 19, 2015

Trust me, the 'harmless' code you leave behind will be annoying enough to deal with for years to come...

@2shraaf

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2shraaf commented Aug 19, 2015

#define j++ i++ 
@miguelmota

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miguelmota commented Aug 19, 2015

oh gawd..

@zerors

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zerors commented Aug 19, 2015

define NULL "NULL"

@petermelias

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petermelias commented Aug 19, 2015

#!/usr/bin/python27

# Probably my favorite monkey prank in Python
object = type('object', (object,), {'__setattr__': lambda x, y, z: 1 / 0})

# almost as frustrating but far too obvious
list = dict
@mokagio

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mokagio commented Aug 19, 2015

😱

@AlphaWhelp

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AlphaWhelp commented Aug 19, 2015

define return throw

have fun

@robbyoconnor

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robbyoconnor commented Aug 20, 2015

I love this.

@kylemsguy

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kylemsguy commented Aug 20, 2015

#define M_PI 3.2f

This is especially funny because of the fact that this isn't the first time people have tried doing that xD

@rreusser

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rreusser commented Aug 20, 2015

What about redistributing the random numbers? It'll only change behavior that's already stochastic… May eventually lead to nagging doubts of randomness…

// Still in [0,1) but with central tendencies:
#define drand48() (acos(1.0-2.0*drand48())/M_PI)

// Extra random:
#define rand() (rand() | rand())

If you use rand() % n with that last one, here's what you'll get for relative frequencies:

                     frequency relative to uniform distribution:
                0     1     2     3     4     5     6     7     8     9    10
          1:  1.00
          2:  0.50  1.50
          3:  1.00  1.00  1.00
          4:  0.25  0.75  0.75  2.25
rand() %  5:  1.00  1.00  1.00  1.00  1.00
          6:  0.50  1.50  0.50  1.50  0.50  1.50
          7:  1.00  1.00  1.00  1.00  1.00  1.00  1.00
          8:  0.12  0.37  0.37  1.13  0.37  1.12  1.12  3.38
          9:  1.00  1.00  1.00  1.00  1.00  1.00  1.00  1.00  1.00
         10:  0.50  1.50  0.50  1.50  0.50  1.50  0.50  1.50  0.50  1.50
         11:  1.00  1.00  1.00  1.00  1.00  1.00  1.00  1.00  1.00  1.00  1.00
@liviutudor

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liviutudor commented Aug 20, 2015

Bloody brilliant! In fact it looks very close to the kind of C++ code I use to write in college :D

@BelfordZ

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BelfordZ commented Aug 20, 2015

@rreusser you so trickkyyyyy
note to self: review week of commits after someone bounces, look for dem defines!

@jep-dev

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jep-dev commented Aug 20, 2015

Since endl is '\n'<<flush...

#define endl flush
@SylvainDe

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SylvainDe commented Aug 20, 2015

I am surprised no one is mentioning the use of trigraphs ( https://en.wikipedia.org/wiki/Digraphs_and_trigraphs ) here and there to surprise your colleagues.

@Spaown

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Spaown commented Aug 20, 2015

Woaw, this is terrorism xD

@auxiliary-character

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auxiliary-character commented Aug 20, 2015

#define union struct
@bhurt

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bhurt commented Aug 20, 2015

My favorite C "gotcha":

define TRUE (2 & 3 == 2)

define FALSE (!TRUE)

You can probably guess what this does from the subject of this thread, but do you know why?

@jotes

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jotes commented Aug 20, 2015

The biggest fuckup here would be a lack of CI and testing.

@alexisvl

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alexisvl commented Aug 20, 2015

auxiliary-character, this one is more fun:

#define struct union
@ThePhantasm

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ThePhantasm commented Aug 20, 2015

define volatile __declspec(thread)

@LYF610400210

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LYF610400210 commented Aug 20, 2015

RUN

@antte

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antte commented Aug 21, 2015

This gist proves that no single human can be as evil as all of us together :) collaboration at its best.

@EskenderTamrat

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EskenderTamrat commented Aug 21, 2015

dumb-dumber

@wojteklu

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wojteklu commented Aug 21, 2015

pure evil

@xylcbd

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xylcbd commented Aug 25, 2015

what's the best evil code ?

@primary0

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primary0 commented Aug 30, 2015

@Dizmaz1

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Dizmaz1 commented Sep 11, 2015

define continue break

@Dracks

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Dracks commented Oct 7, 2015

@jotes The solution it's here: https://github.com/hmlb/phpunit-vw The VW CI module! :)

@Gonzalo-Z

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Gonzalo-Z commented Oct 9, 2015

Me as a QA Engineer reading this...

scared

@Alhadis

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Alhadis commented Oct 24, 2015

This. Is. Brilliant.

Holy shit.

@shirlston

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shirlston commented Oct 24, 2015

My C is a little rusty, but I think this would break everything. (Hint: the second one isn't a semicolon)
#define ; ;

@tokoroten

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tokoroten commented Oct 29, 2015

#define long int // for non 32 bit env
@jimgao1

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jimgao1 commented Oct 29, 2015

The look on his face when your friend discovered this....

@felipou

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felipou commented Nov 10, 2015

One can also do this to break a single computer:
alias g++="g++ -include /path/to/evil.h"
This way the source files and the repository remains intact... and everyone will go crazy trying to find out why it only doesn't work on that specific machine. Or those specific machines, if you can manage it.

@Ir1d

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Ir1d commented Nov 26, 2015

@shirlston

Guess you would like to take a look at this.D

https://github.com/reinderien/mimic

@finnoleary

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finnoleary commented Dec 3, 2015

/* create memory leaks if run on April, 1st -- requires time.h (UNTESTED) */
#define free(n) if((date() - 777600) % 31556926 < 86400) malloc(n); else free(n)
@ferrywon

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ferrywon commented Jan 5, 2016

I'm your BOSS!!! Coming my office NOW !!!

@slashbinsh

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slashbinsh commented Jan 6, 2016

(True, False) = (False, True)

@fisher

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fisher commented Jan 6, 2016

#define close(...) /* very special GC workaround */

@teschdominic

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teschdominic commented Jan 10, 2016

what does this do

@norbekaiser

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norbekaiser commented Mar 16, 2016

how about^

#ifdef EXIT_SUCCESS
  #undef EXIT_SUCCESS
#endif
  typedef void (*EXIT_SUCCESS)();

#ifdef EXIT_FAILURE
  #undef EXIT_FAILURE
#endif
  typedef void (*EXIT_FAILURE)();

@Tatsh

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Tatsh commented Mar 20, 2016

Somewhat easily detected but need some OS X/iOS/Objective-C stuff here:

// The obvious
#define YES NO

// Make the preprocessor think you're targeting a very early version of Foundation (probably has to be above #import)
#undef NSFoundationVersionNumber10_10
#define NSFoundationVersionNumber10_10 NSFoundationVersionNumber10_0

// Replace all immutable types with mutable!
#define NSArray NSMutableArray
#define NSDictionary NSMutableDictionary
#define NSSet NSMutableSet
#define NSData NSMutableData
// and so on

// Mess with memory
#define __weak

// Put your favourite exception message here
#define NSLog(m, ....) NSLog("Uncaught exception ...")

// Mess with transformations, possibly animations
#define GAffineTransformMake(a,b,c,d,tx,ty) GAffineTransformMake(a+1,a+2,c+3,d+4,tx-1,tx-2)

// Always return an error
#define SecItemCopyMatching(a, b) errSecNoSuchClass
// Useless error message
#define SecCopyErrorMessageString(a, b) CFSTR("Secret error")
@Redwan13

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Redwan13 commented Mar 25, 2016

Things to commit just before leaving your job

Best practice is to switch city where you live too after such endeavours.

@ojno

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ojno commented Mar 25, 2016

#ifdef DEBUG
#undef DEBUG
#endif

#ifdef NDEBUG
#undef NDEBUG
#endif

And so on...

@cdevr

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cdevr commented Apr 8, 2016

class ThereIsNoAbsoluteTruth:
def nonzero(self):
import random
return random.randint(1, 1000) < 1000
def str(self):
return "True"
def repr(self):
return "True"

True = ThereIsNoAbsoluteTruth()

@Link512

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Link512 commented Apr 8, 2016

ifndef DEBUG

define true false

endif

Same stuff with NDEBUG. The idea is only to do this in release mode.

@mabm

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mabm commented Apr 9, 2016

Wahoo .. You are my hero +1

@llxp

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llxp commented Apr 9, 2016

How about wrapping a system dll under Windows and putting some of this evil stuff in it xD

@macedigital

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macedigital commented Apr 20, 2016

Holy crap! And I thought operator overloading (e.g. http://stackoverflow.com/questions/1098303/what-makes-scalas-operator-overloading-good-but-cs-bad) was crazy 🙈 All hail the macro 😄

@hanbang-wang

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hanbang-wang commented Apr 27, 2016

The random part truly works most of the time (don't ask me why I know it

@lovemo

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lovemo commented Apr 28, 2016

crazy 😄

@seven1240

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seven1240 commented Apr 29, 2016

Cool

@nellochen

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nellochen commented Apr 29, 2016

never say a word...

@wangrenjun

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wangrenjun commented May 3, 2016

undef __cplusplus

@msierchio

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msierchio commented Jun 30, 2016

A thing of beauty is a joy forever.

@roman-alexeev

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roman-alexeev commented Aug 10, 2016

#define __STDLIB_H__ 1

@wizard97

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wizard97 commented Aug 14, 2016

#define sizeof(x) sizeof(x)+1

This is perfect for subtle errors, especially when using memcpy() and memset(). Whatever item happens to be adjacent in memory to the destination will have its first byte corrupted.

@wizard97

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wizard97 commented Aug 14, 2016

static jmp_buf _evil;

#define if(x) setjmp(_evil); if(x)
// Redefine some keywords :)
#define break do { if(rand() > RAND_MAX * 0.99) longjmp(_evil, 1); break; } while(0)
#define continue do { if(rand() > RAND_MAX * 0.99) longjmp(_evil, 1); continue; } while(0)

Ahh, random occasional longjmps that could do one of several things:

  1. Jump to the last time an if statement was executed
  2. Jump into a call frame that no longer exists causing undefined behavior
  3. Segfault
@kvpb

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kvpb commented Aug 22, 2016

I find you guys rather stingy with your future former colleagues. Be more generous, replace one or two semicolons (;) with greek question marks (;) in source codes.

screenshot 2016-08-22 at 15 03 43

screenshot 2016-08-22 at 15 03 53

Though some compilers might help spot this, it should work as long as error messages don't make it look too obvious. Don't mention it. You'll thank me later.

@ghost

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ghost commented Sep 12, 2016

Tears of joy .. Brilliant

@onlurking

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onlurking commented Nov 12, 2016

Awesome production code, buddy.

@michaellee8

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michaellee8 commented Dec 4, 2016

how about

#define == =

@jokester

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jokester commented Dec 9, 2016

#define << >>

@sergeysychov

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sergeysychov commented Dec 16, 2016

void __cxa_allocate_exception() { /*do nothing*/ }
void __cxa_throw() { /*do nothing*/ }

No exceptions = no problems

@TheRoyalGhost

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TheRoyalGhost commented Dec 29, 2016

#define True False
#define False True
#define void Null

@JanWosnitza

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JanWosnitza commented Apr 25, 2017

#define rand() (__LINE__ ^ (*static_cast<int*>(__TIME__.[4]))
@WestFive

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WestFive commented Apr 26, 2017

img

interesting

@ghost

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ghost commented May 25, 2017

//insert super complex code that does important work
int main() {
  return 0;
} //sneak this in :smile 
//actual code

or even better

//insert super complex code that does important work
using namespace std;
#define cout cin
#define cin cout 
//actual code

or the good old variable name trick:

//insert important code
int foo;
int bar;
int temp;
int stuff;
int a;
int b;
int c;
int d;
int e;
//etc
//more important code

Time consuming, but definitely will make people angry.
Put this in a local scope to make people very angry.

@AndrewDavis

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AndrewDavis commented Jul 28, 2017

My favorites + some of my own alterations (for c++):

#ifndef DEBUG
#define if(x) if (x && (__LINE__ % 6 == 0 && rand() % 1000 == 0)) //On rare occasion, any if statements on every 6 lines of code should fail.
#define j (rand() % 1000 == 0 ? i : j) //Should never use these anyways... Usually j is used in the inner loop.
#define union struct //Still "runs"...
#define double float //Efficiency, no?
#define delete //!!!NEIN!!!
#endif

(Note: upon a later glance, I had doubts that the #define j will work; but, according to this link, it will: https://stackoverflow.com/questions/11494988/using-ternary-operator-to-initialize-a-reference-variable)

@rjamesnw

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rjamesnw commented Oct 13, 2017

lol

@michaellee8

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michaellee8 commented Nov 4, 2017

Any JavaScript/node.js version for this? Xdd

@Fer0x

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Fer0x commented Nov 21, 2017

image

@twoscomplement

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twoscomplement commented Feb 2, 2018

Runtime randomness is great, but have you considered adding a compile time RNG? ;)

@ramonsaraiva

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ramonsaraiva commented Feb 22, 2018

https://github.com/ramonsaraiva/init python thingy inspired by this 😄

@johnbsys

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johnbsys commented May 24, 2018

tenor

@knyzorg

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knyzorg commented May 24, 2018

ITT: people who don't know how to code block

@AnrDaemon

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AnrDaemon commented Jun 15, 2018

Reminds me why do you need CI and tests.

@drewchapin

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drewchapin commented Jun 29, 2018

What would be really fun would be placing them in <Windows.h> on the developer machines and build server(s). Use conflicting #defines randomly between each so that the effects are different depending on who's compiling the code.

@tigerssj

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tigerssj commented Jul 6, 2018

your boss loves you....

@FractalXX

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FractalXX commented Sep 6, 2018

#define for for(int evl = 0; evl < 10; evl++) for
#define while if(0) while

@tconnel

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tconnel commented Oct 8, 2018

do NOT fire @aras-p.
this is beautifully evil.

@rotomhp

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rotomhp commented Nov 2, 2018

#define + -
#define - +

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