Re: My C arrays are too large

[Lee <ler762@gmail.com>]

On 9/13/19, Jose Isaias Cabrera wrote:
>
> Achim Gratz, on Friday, September 13, 2019 02:39 PM, wrote...
>>
>> Blair, Charles E III writes:
>> > My apologies for failing to reply on-list.  I don't know how :(
>> >
>> > My machine is 64 bit, and I hope I installed the correct version of
>> > cygwin.
>> >
>> > This program:
>> >
>> > #include<stdio.h>
>> > int main(){char *a[50][8192];
>> > return 0;}
>> >
>> > compiles with gcc  (no special options) but gives "Segmentation fault".
>>
>> You are creating an automatic variable that's larger than the default
>> stack.  You need to enlarge the stack, either during link time or later
>> e.g. via
>>
>> peflags -x0x800000 a.out
>
> This is great! Thanks.
>
> But, let's talk about this a bit... Shouldn't the compiler provide some
> warning, and also, it should never blow up with a "Segmentation fault".  I
> believe there should be some type of Out Of Memory error, or something like
> it.  But now just blow up.  Anyone thinks like me?  Just my 102 Dominican
> cents ($1 = $51 Dominican). :-)

Yes, it would be nice if you got an error message.  But once you
notice a .stackdump file has magically appeared, then
$ gcc -o a.exe starray.c

$ ./a
Segmentation fault (core dumped)

$ cat a.exe.stackdump
Exception: STATUS_STACK_OVERFLOW at rip=001004010C6
  <.. snip ..>

Search for "cygwin STATUS_STACK_OVERFLOW" and find
  https://github.com/OpenFAST/openfast/issues/144

which gives you
$ gcc -o a.exe -Wl,--stack,0x1000000 starray.c

$ ./a

$ peflags -x a.exe
a.exe: stack reserve size      : 16777216 (0x1000000) bytes

Regards,
Lee

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