gcc -fexceptions

This one goes to all the devs out there...

Can anyone tell me if our GCC 4.2.4 or higher (5.3.0) support exceptions?

And where do i use the -fexceptions flag? GCCFLAGS or LDFLAGS?
Is there anything special i need to take into account? e.g. more flags i need to set to make exceptions work?

Reason for asking is, one of my maintained projects switched to using exceptions lately and now native compiling breaks.
I have already tried and added the flag to both LD and GCCFLAGS (one after the other) to fix the error, but to no avail.

I need to know if it is even supported in our adtools, so i could file a feature request to add it if needed.

Thanks in advance

@Raziel

You mean C++ exceptions? They are only supported in single threaded mode as far as I recall.

@broadblues

I guess so.

Doesn't work, no matter what i use.

The project reverted those exceptions changes for now and it starts to build again.

Too bad, once they decide to go with them, this project will be another nogo for AmigaOS.

@Raziel

Did you mean CFLAGS? -fexceptions is recognized as an option on the 3 versions I tested, 4.2.4, 5.4.0 and 6.1.0. Whether it actually works or not, I have no idea.

Are you statically linking? I've only had C++ exceptions work properly with static libs (see bottom of post #25).

Are not exceptions working by default (even without -fexceptions)?

@Raziel Could you provide an example and the error you get?

Sorry for the long delay, a day has just too few hours...wonder when the gouvernemnt will do something about that

@MickJT

I meant CXXFLAGS, sorry for the confusion

I link statically, yes

@corto

Only that lines from the project that errors out on compiling:



Here is the change (amongs others) in ldo.cpp that broke it:


The code is here.

The change has since been reverted (partially) and is now working again.

Mick noted that it might have been a bug in the code...

It seems there was at least one problem in the code:

try {
tf = bin ? luaU_undump1(z) : luaY_parser(z);
status = 0;
} else {

I'm not a C++ expert but it seems that throwing a char string is not a good ideally, an exception type should be preferred.

About the error "exception handling disabled, use -fexceptions to enable", I don't know ... I tried a similar case in a short example here and it works with g++ 5.4.

By the way, if you still use 5.3, you should update to 5.4, so you will be able to report some problems about the version that is in development here:
https://github.com/sba1/adtools/issues

@corto

Where can i get 5.4?

So here is trivial exception handler



Compile and test two different ways

Quote:

So yes exceptions work. (that was gcc 4 on my SAM but I doubt it would differ on gcc 5 (but it's not impossible))

Make sure that -fno-exceptions is not defined any where in the makefiles

Also I doubt think

try { } else { }

is valid c++

should be

try { } catch { }

Though I'm a lousey c++ coder so might be wrong there, the error out suggest that's what the compile time problem is.

@Raziel

Native compiler for OS4 and OS4 cross-compiler for Debian based Linux are available here:
https://github.com/sba1/adtools

That's well explained in the readme, that gives a link for direct download.

I use the latest:
https://dl.bintray.com/sba1/adtools-na ... ools-os4-20170623-404.lha

@Raziel

gcc 5.4 is on the adtools site in the bintray link therein.

If you are using the gcc 5.3 from os4depot that is definitly broken is some regards (sorry I forget which off hand and they may not be relavant here)

@corto

Thank you, i will try that

@broadblues

Nice

Was there a alert somewhere that 5.3 is broken?

@all

Well, with 5.4.0 in place and a reboot later, i now get this on configuring

Quote:

The file is there in root, so cat is wrong

and an incomplete makefile

Quote:

The same works fine with 5.3.0...any pointers, please?

@Raziel

remove the coreutils that got mixed in with the ggc:bin they are broken and the position in the path overides the working ones in SDK:Local/C

@broadblues

Thank you

Is that because it's a non-released version?
Why are there broken components in adtools?

@Raziel

It an unofficial build. Albeit the most official unofficial build

They are broken because they were built against newlib rather than clib2 and there are a couple of differences with command line handling pattern matching (or when not to) etc. between the two libs.

Naturally the author didn't realise they were broken when the archive was built...


There is a bug report against the issue on the adtools github website

@broadblues

I see, thank you again

Will reconfigure and compile all my projects and if anything comes up may bother you again

@broadblues

gcc5.4 is also erroring out at the same lines with the exact same error, so it's at least not gcc's fault.

@broadblues

wrt to sobjs builds.

I get a crashing sobjs exe with both gcc 5.3.0 and 5.4.0, both crash in libstdc++.

I know that it used to work (to an extent; at least the exe wasn't crashing) in 4.2.4.

Crashlog