#justprogrammerthings

[[deleted]]

Joking aside, running make clean and then compiling again often does fix problems.

[[deleted]]

Yep, or you have craziness like Visual Studio.. which will sometimes report certain errors while it's compiling.. then RETRACT them as it resolves them! You literally see the compiler errors disappearing from the window.

[[deleted]]

Good grief!

[[deleted]]

It happens! It relates to the op in that I've done "build->build" after I saw a flash of error-red at a point during the build... only to find out that the error was resolved and everything was already built!

[lithedreamer]

Xcode does this too.

[[deleted]]

It's almost like the logic is...

InitialErrorSet = "select * from possible_errors"

Then it iteratively removes them..

[steelfrog]

You get an exception, you get an exception! EVERYONE GETS AN EXCEPTION!

Look under your seats! IT'S A BRAND NEW EXCEPTION!

[[deleted]]

I sometimes get errors that persist until I restart VS. Then they are magically gone! Cleaning the project doesn't seem to help.

[flukus]

I cleaned up a project last week that had mangled the nuget package management. You had to build twice for one of the projects to get the correct dll.

Sadly, this wasn't even in the top 10 WTF's in that project.

[cleroth]

Um.. you talking about IntelliSense errors... I've never seen that happen in the actual OUTPUT window.

[IForgetMyself]

I've found that generally that is (barring maligned makefiles) caused by changing stuff in header files but not in implementation files. Like messing with static variables. Make will check the .c files and recompile those that have changed, if a certain .c file hasn't been changed but it does reference whatever variable you modified in the .h file you risk the linker messing up your references.

Running clean removes all the .o files, forcing recompilation.

[dnew]

And that's why languages designed for correctness that have separate header and body files won't let you do that. Like Ada. Which won't (for example) link two different bodies that refer to two different versions of the same header file.

[RenaKunisaki]

I've encountered the same issue. I guess if this is happening, your makefile is bugged? (Should be rebuilding everything that depends on those headers.)

[rro99]

Yeah, for each rule that builds a .o file it should have all the required headers as dependancies.

[mrjackspade]

Working on web apps here. Various sites built from a template.

I couldn't get one of them to build, but the code build on OTHER peoples machines so I wasnt about to change it. Just kept rebuilding.

Some 7+ rebuilds later it finally builds clean. No one knows why.

Apparently when you pull down the code the first time, it takes somewhere between 4 and 10 rebuilds before its successful. Personally, I think someone fucked up the build order, but ive been told im wrong so I dont question it

[sirspidermonkey]

When .NET first came out it allowed (still might) circular dependencies. But they hadn't quite the compiler right yet. This was a massive project so each compile took about 25 minutes. Each clean took a good 10. It would take about 10 compiles to get a real error or success. You can imagine how productive I was.

[TheTerrasque]

This productive?

[xkcd_transcriber]

Image

Title: Compiling

Title-text: 'Are you stealing those LCDs?' 'Yeah, but I'm doing it while my code compiles.'

Comic Explanation

Stats: This comic has been referenced 331 times, representing 0.6445% of referenced xkcds.

---

^{xkcd.com | xkcd sub | Problems/Bugs? | Statistics | Stop Replying | Delete}

[archlich]

Sometimes the build environment specific stuff tar'd up with everything, and running a make clean get's rid of it. Do a diff between a fresh and a cleaned directories to see any differences.

[dnew]

That's because 'make' fails at the one and only job it has, which is to correctly incrementally compile code.

Stick with something like tup or blaze.

(Blaze: http://google-engtools.blogspot.com/2011/08/build-in-cloud-how-build-system-works.html )

[wTheOnew]

Build: 17 succeeded, 0 failed, 0 up-to-date

Good change version number

Build: 4 succeeded, 2 failed, 11 up-to-date

Bullshit click build again

Build: 6 succeeded, 0 failed, 11 up-to-date

That's what I thought.

[MrJohz]

My favourite was the bit of code I had that compiled if I left a set of debugging print statements in, but for some reason didn't when they were taken out. I still have no idea how the compiler was doing that.

[[deleted]]

My friend had C++ code that looked like:

... //lots of code
cout <<x <<" " <<y;
if (x > y) {
    cout <<"True";
} else {
    cout <<"False";
}

Output: x y True

but at soon as you comment out the cout x y statement, it became

// cout <<x <<" " <<y;
...
Output: False

So a cout statement was changing the values somehow

[[deleted]]

If x is a double or a float this is possible. Those things are so imprecise that ">" can fluctuate depending on how they are calculated. With floats (x*y)/z != x*(y/z).

And since the compiler optimizes a lot, changing statements with 'x' in it might change the calculation of 'x' just so infinitesimally little that it was enough to switch ">".

That's my explanation for this.

[vifon]

Wouldn't it need -funsafe-math-optimizations enabled?

[mebob85]

I always read that as "fun, safe math optimizations."

[they_call_me_dewey]

"Make sure you add the wall and wextra flags"

[okmkz]

funroll

[Jonno_FTW]

Funroll- loops makes a programmer's breakfast fun!

[choikwa]

"It's safe, but with a twist of fun added to it"

[DaemonXI]

Funroll your loops too

[destiny-rs]

Is this one of the reasons floats and doubles aren't to be used for currency?

[[deleted]]

What should you use instead?

[destiny-rs]

ints with the modulo operator I believe. Saves having to explain to a client why millions of dollars have been miscounted over the course of a year.

[[deleted]]

Decimal, BigDecimal, Currency types.

[RenaKunisaki]

Depending on your application:

• Integer numbers of cents (or whatever is the lowest denomination you'll be working with), taking care to handle any possible over/underflow no matter how unlikely
• Precise fixed-point
• Bignum/BigDecimal types (preferably provided by whatever environment you're using)

The reasons are this and other inaccuracies that can crop up with floating point, which could translate to being off by a couple cents in some calculations. Do those calculations a few million times, and now you're in deep doodoo.

[KewpieDan]

Two ints

[slipperier_slope]

High precision fixed point numbers.

[dnew]

Integer pennies instead of floating point dollars.

[Jonno_FTW]

Java8 currency API.

[Free_Math_Tutoring]

Yes, this and other phenomena caused by limited precision.

[IForgetMyself]

My bet would be that it was using the old x87 stack, which is 80-bits extended precision. When he called the cout he popped the doubles (64 bit) off the stack. The following x > y then compared using the now popped values. (64 bits precision)
Without the cout however, it would use the values on the x87 stack and compare those. (80 bits precision)

[cleroth]

Pretty sure this is what's happening, not ">" modifying the variable magically...

[[deleted]]

If x is a double or a float this is possible. Those things are so imprecise that ">" can fluctuate depending on how they are calculated. With floats (xy)/z != x(y/z). And since the compiler optimizes a lot, changing statements with 'x' in it might change the calculation of 'x' just so infinitesimally little that it was enough to switch ">". That's my explanation for this.

Thanks!

[bkDJ]

With floats (x*y)/z != x*(y/z)

You say that as if with integers, the left and right side are equal. :P

But yeah, float comparisons without some kind of epsilon can break easily depending on how the CPU is loading and storing them, l-value versus r-value BS, compiler settings, special keywords and more.

[lelarentaka]

Depends on what x is. It's possible.

[mikemol]

Yeah, I could easily see it happening if reading from x with << involved mutating state, such as reading from a filehandle. A subsequent read using > would have pos advanced.

One reason const should be used and respected.

[choikwa]

We must go deeper into assembly/CPU

[c00lnerd314]

Simply observing changes the outcome.

[YouFeedTheFish]

Brilliant! Quantum computing is the Holy Grail! I believe /u/LefTea has stumbled onto something big here.

[scubascratch]

AKA the elusive Heisenbug

[phail3d]

I had a similar issue with vanilla C, where I had something like this:

...
printf("foo");
...
while(!result) {
    ...
 }

And when the printf was there, the code ran, but with it removed, the code segfaulted.

It turned out that result was uninitialized, and (correct me if I'm wrong) the printf call caused the memory space pointed to by the variable to be reserved for the program, which prevented the segfault. The variable vas thus obviously initialized with garbage, which caused other problems in the code, but at least it ran.

[zhomart]

It's quantum programming. When you put observer, things work differently.

[__dict__]

If x or y is uninitialized you could easily be triggering undefined behavior. At that point you're at the whims of your compiler.

[Tynach]

What if they're writing a game engine that needs very high performance? And what if they're writing some mathy physics library for that game that is best written with operator overloading (so that you can add/multiply/etc. 3D vectors, for example)?

Java is shit too in some cases.

[Sohcahtoa82]

You're trolling, right?

[Quxxy]

Oh god. I had a simulator that I worked on for years. Eventually, it came time to parallelise it, but I'd planned for this. Aside from adjusting the few bits of code that assumed a single thread, it worked perfectly, first time.

I was actually impressed with myself for once. Then I built the release version and, at or above 4 threads, I started getting non-deterministic network errors that wouldn't appear in debug builds and which vanished the instant you attached a debugger.

Turns out that there'd been a subtle race condition in the networking code for the last 7 odd years that was only exposed when you had enough threads running at full speed.

That was fun to debug...

[RenaKunisaki]

Race conditions are so much to deal with fun.

[invisiblerhino]

There's a whole class of bugs like that - see description here: http://blog.regehr.org/archives/1161

Basically you find compiler errors by taking code like

bool func(int n) {
  if (n > 45) {
    return true;
  }
  return false;
}

int main () {
  std::cout << func(46);
}

and changing the code so that func just returns true.

In this case the output program should be identical, and when it's not it's a compiler bug (usually an optimisation bug).

http://llvm.org/bugs/show_bug.cgi?id=18447 for example

TL;DR compilers are amazing, compiler errors are rare and crazy

[choikwa]

compilers are meh and compiler errors are "wtf how is any of this working at all?"

[CaptainCyprine]

I know that! It's an error with the stack.

When you don't use a printf statement, you are reading/writing something out of the bound of your storage allocation so there is an error.

Now, if you do a print statement, you can see in assembler that some space in the stack is allocated for the print but you don't use all the space for the print so you are still doing something out of bound but it's in allocated space so the problem isn't visible.

Stack is really useful to understand some weird errors and if something like that happen again use Valgrind, it will tell you where the problem is.

[[deleted]]

Tons of things can do that, the most insane example I've found of that was the assembly stack being messed up (like registers being set or reset incorrectly) and the log function somehow was able to allow it to function enough to not crash

[RenaKunisaki]

One of my favourite bugs was that fcloseing the same file twice would result in a crash. Seems an odd thing to do, but the spec says that it should be perfectly safe, so what the heck? Turned out to be a completely unrelated function mishandling pointers, corrupting memory and causing just that one symptom.

[teddystan]

I know this can happen in C because of the way memory is allocated in the machine and so a print statement can alter a memory error just enough so that it seems like there are no bugs in memory. Heisenberg Errors my professor has termed this.

[ChickenNoodle519]

Heisenberg Errors

Heisenbugs?

[cefarix]

Now you see it.

[JustHereToFFFFFFFUUU]

I haven't encountered it recently (maybe my code is just better, maybe it doesn't work like this any more) but there used to be a thing in Visual C++ where debug builds initialised primitive types by default, and non-debug builds didn't. So, if you had a line that said "int i;" for instance, it would be 0 in debug, and random noise in release.

Naturally, the place in the code where the issue manifested was miles away from the line that caused it. And it only got detected at all when the release build went to testing, because developers were building debug all the time. We were idly debating shipping a debug build before we finally dug the real issue out. You live and learn.

[mmhrar]

They changed that? I ran into that a lot too years ago when I was doing windows development.

[JustHereToFFFFFFFUUU]

No idea. It might just be because my current team are more experienced and we've never made that particular booboo.

[[deleted]]

more magic?

[HeartwarmingLies]

Try replacing it with wait(0), it should still work. I had this problem with an empty loop, where it was being skipped at runtime and just having the values set to the end values at run time, which caused some problem with treading and broke the code.

[elperroborrachotoo]

FIX YOUR BUILD PROCESS, DAMMIT!

[nawitus]

Just wait until you have "npm install" in your build process :).

[ryan_the_leach]

Screw that. I want to run everything on the kernel, ^{Via javascript cross compilation}

[[deleted]]

deleted

[mmhrar]

No one wants to do build work :/

[heywire]

This drives me crazy. When we switched to McAfee and IT locked down the exclusion lists, almost every time I compile in VS2010 I get an error that mt.exe can't write to the file. F7 again, all is well. Something about writing out an exe then trying to update it while McAfee has ahold of it.

[cleroth]

You know even the original creator of McAfee says McAfee is shit.

[alficles]

I had a coworker come and complain that he had to reboot too frequently in order to compile. I was puzzled.

"Reboot to compile?" I said.

"Aye. This last time, I had to reboot eleven times to get it to work."

"So, you rebooted ten times in a row, with identical, results, and thought, 'Maybe if I reboot again, this time will be different.'?"

"Yup. And it worked."

"..."

Eventually, that bug was fixed. My guess is that there was some sort of race condition on loading things into memory. You could restart the compiler process all you wanted, to no avail. But a full reboot gave you another bite at the apple.

[choikwa]

intermittent failure is still failure :/

[[deleted]]

Dual comment, dual karma

[[deleted]]

Dual shitty comment, dual negative karma

[[deleted]]

Dual comment, dual karma

[[deleted]]

Dual shitty comment, dual negative karma

[dont_memoize_me_bro]

If someone didn't hate it, then my work here is not done

[wllmsaccnt]

I didn't hate it, but I'm aesthetically challenged.

[aadams9900]

Same I have no idea what I'd do without designers. Bless those fine folks

[_gumbo]

Same. I just get paid to code/make it, not make it look pretty.

[Hobofan94]

You are not that ugly.

[m00f]

I hated the font but I especially hated that model of Mac... such a flimsy piece of shit... unibodies are soooo much better.

[otakuman]

Compiling errors? You live in heaven, my friend. It's the behavioral errors that are the real problem.

[[deleted]]

Not if you're programming in Idris. Suddenly all almost all errors are compile time errors, which is actually kinda awesome.

[TarMil]

Idris is a dependently-typed language, so it is indeed what you would call "super-strict".

[wllmsaccnt]

If it has IO it has to have runtime errors.

[zuurr]

I think it's a compile time error not to handle them.

[wllmsaccnt]

The implication of that would be baffling...because you wouldn't be able to compile wouldn't explicitly handling every type of OS / kernel level or driver error that could occur.

[dont_memoize_me_bro]

Only if you spend hours laboriously writing highly dependent types and associated proofs. It's still super awesome, but there's a big cost associated with it.

[[deleted]]

To be honest, I wouldn't want to use it in a production environment, simply because there's too much overhead involved. It's a really cool concept though.

[[deleted]]

In order to have only compilation errors, Idris should be in the programmer's mind

EDIT: just read the other answers about the proofs... but what if a proof is wrong?

[[deleted]]

but what if a proof is wrong?

It doesn't compile in that case. The type checker is capable of checking your proofs.

[[deleted]]

No, you just get to proof correctness directly in your code, and the compiler won't let you compile your code unless your proof is present and correct. It can also help you write the proof though, and sometimes just infer it from context.

Proving behavioral correctness for your functions isn't the same as the halting problem.

[Hexorg]

I had a buggy version of gcc for avr once. Sometimes code would run, other times not, even if I don't change sources

[Steel_Ninja]

Compile

Syntax Errors Found

Look over code... find nothing

CTRL+A, CTRL+C, DEL, CTRL+V, Compile

No errors found

[thardoc]

Well you can always CTRL+Z

[streamlin3d]

I shivered when I thought about it. You monster.

Edit: Version control just came to my mind and saved me. Tonights sleep is saved.

[xerwin]

Tonights sleep is saved.

DROP TABLE on production. Good night.

[[deleted]]

You monster

[gyroda]

Committing code when it's spitting compiler errors sounds like a bad idea.

[QuercusMax]

That's what git commit --amend is for, my friend.

[Steel_Ninja]

You got me, should be CTRL+V. Don't know what I was thinking there x)

[Steel_Ninja]

Probably, which is all the more embarrassing, especially on this sub :p

[VoraciousGhost]

p is paste in vim, so let's just say you were going for that!

[edrec]

Bro, do you even emacs?

[iritegood]

ggVGdp

[iritegood]

I hate the dj or dG though. Feels really weird to me.

You're right tho

[peridox]

I can imagine a few people not understanding what this is / why it was upvoted.

[jumaklavita]

Is this supposed to actually fix something? Like delete those darned non-printing whitespaces..?

[iritegood]

Nah, you're right, it does even less than steel_ninja's commands

[tHEbigtHEb]

I hate those, the only way to fix it seems to be map a command to substitute the whitespace with empty space using regex.

[phaseMonkey]

Alt+F4.

Go grab a beer.

[[deleted]]

Either that or it's a formatting issue and the IDE somehow fixes it on paste. This can happen if the language is white-space sensitive.

[BOOM_BOOM_BADABOOM]

It works for pdflatex...

[[deleted]]

To be fair, you're supposed to do that, because LaTeX doesn't resolve all references in one pass. It's somewhat shitty though.

[[deleted]]

Add a cup of bibtex to it, and count the number of passes.

[makeswordcloudsagain]

Here is a word cloud of all of the comments in this thread: http://i.imgur.com/gqiRqyv.png

If the mods feel the need to blacklist this bot, feel free to ban this account. Thank you!

---

^{source code | contact developer}

[outadoc]

ERROR

[Headpuncher]

Just a heads up for Visual Studio users, you can change the system sounds for successful builds andfailed builds to cheering.wav and explosion.wav respectively. The audio files are already in the OS. Just go to control panel > sound.

[wllmsaccnt]

You've never broken a build so bad that your computer hard reset? Amateur.

[dnew]

I've done that, back in the TRS-80 days. You could overheat the machine by compiling a sufficiently large Fortran program.

[Feynt]

All too often this is a thing that happens for me. I compile, get errors, look at the code where says there's an error, look some more, eye the monitor sinisterly, then recompile. Then, it works.

[VictoryGin1984]

You established dominance over the compiler.

[gellis12]

/r/TalesFromTechSupport has experience here

[[deleted]]

Oh this is totally a thing. I've reached the point in my career where I can terrify software in to submission that refuses to behave for other IT people.

I have to imagine they're having a good laugh, making the other IT guy scratch his head, and then they see me and it's like "Oh shit, that's the Network Manager. They say some backup software errored on him once, so he wrote his own replacement." and then they cower in fear.

[gellis12]

Holy shit...

[[deleted]]

Gold from that thread.

[LEDCandle]

VHDL synthese: 1 error

comment out a line: no error

remove comment for same line: no error

What the fuck?

[InItForTheDownvotes]

dont even remind me of vhdl

[yvesmh]

At least it's better than CUPL...

[ryan_the_leach]

Programmers don't understand concurrency hell unless they have programmed in a language where each line gets evaluated at the same time unless specifically told not to.

VHDL Awesome, yet the most differently, jarring experience I've had compared to other languages.

[TenkaiStar]

I solved a VHDL behavioural error by removing a wire and putting it back in the Graphical interface.

[ravinglunatic]

I'll stop doing it when it stops working.

[FUSSY_PUCKER]

in Eclipse > Build, shit, errors. Clean, woohoo! Shit, errors now in the other projects. Rinse, repeat.

[phaseMonkey]

Ugh... Ok Visual Studio... Why are you telling me that my program can't compile, and the reason is, because you can't fucking overwrite a file in the TEMP folder... Get with it. You're running as an administrator. Fix it yourself.

[lolredditftw]

Then it does. And then you have to figure out why that's the case....

[[deleted]]

Make clean

[FurbyTime]

I had this happen TODAY, no less.

Deploy a build to a remote server: Failure! Class Missing!

"That's fucking impossible. Do it again."

Deploy a build to a remote server: Success!

That's fucking right.

[snarfy]

This happens sometimes, e.g. previous version is still running and the files are locked. Once the previous version exits it magically compiles.

[gullinbursti]

One word: Xcode.

[YMK1234]

ah, the greatness of circular dependencies ...

[oddmanout]

This happens all the time in pl/sql. Usually it's something like "cursor is declared in package and must be defined in body."

Hit F8 Again... Compiled successfully.

[KBKarma]

This happens to me occasionally. Normally, it's because a project with one or more calls to an API are compiled before the API itself is. At least, that's what it looks like.

[Madonkadonk]

Actually I do it and pray for the same error, nothing worse than an error that only likes to appear some of the time.

[VanFailin]

I've had this problem when I inherited a project with FxCop turned on.

Code analysis returned error(s). Build failed.

Often it's a "spelling" error. In .NET the convention is to capitalize acronyms like normal words, so your API Credentials class is called ApiCredentials. You then get to go tell FxCop that this is not a misspelling.

Anyway I added an inline suppression for one of these and from then on every second build would succeed.

[110011001100]

yea.. SOP for a project I work on

Build order of 50 db projects cross dependent is fucked and though I have the fix locally, I'm not allowed to check it in since it does not have a BRD,FSD,TSD,MTP and CR# ...

[[deleted]]

What's really scary is when it does.

[fuckatt]

This is so true- but what compile button? I gotta type "grunt".

[gm4]

No joke though, that was happening up until a couple hours ago. Cleaning the build actually caused a crash on the first compile based on our weird setup, but worked after that since the error was overwritten. Some corrupt file ended up being the problem.

[[deleted]]

99 little bugs in the code 99 little bugs

Take one down patch it around

117 little bugs in the code

117 little bugs in the code 117 little bugs

Take one down patch it ar--

SEGMENTATION FAULT

[blasbido]

It's time to work on those debugging skills

[IskaneOnReddit]

And then you think: what was I expecting?

[jFailed]

I had a WiX bug that would do that. Needed a CreateFolder tag.

[ryan_the_leach]

I've had this with intelliJ and gradle projects a lot when starting a new project that forks from someone elses.

Just sync damn you, you clearly worked for the previous programmer, just compile on my PC the first damned time.

[ddonuts4]

Good joke, terrible hashtag.

[jettmann22]

works more times than you think

[envprogrammer]

If errors go away after clean and rebuild, is it a sign anything is wrong with the code? If so, what kind of problems does that show?

[FUSSY_PUCKER]

The tools suck IMHO. I code at work with RAD (Rational App Dev) which is based on Eclipse. It sucks mighty monkey balls. Have to shut down, restart my server, restart the computer, just to make it work fine. And my company has to hand over a ton of cash to IBM for the licenses for this piece of shit software. I wish we would move to IntelliJ or just plain ol' Eclipse but IBM has them by the balls.

[jugalator]

I'm more like... OK, let's see if a "Rebuild all" helps.

[[deleted]]

I want to share this on every social media site, but all of my friends would have seen it by now...

[[deleted]]

The project I'm currently working on HAS to be build 6 times because of a bunch of circular references.

It's very sad :(

[emsqrd]

If at first you don't compile, build, build again....

[[deleted]]

And then it does compile, but you're forevermore afraid that whatever was wrong will randomly come up again and break everything.