On Friday, 8 September 2023 at 13:05:47 UTC, evilrat wrote:
You run with -unittest compiler flag? Well, that does nothing
for me with betterc (without it is ok).
I did stupid and unsafe things like malloc(0) and writing out
of bounds but still no crash, it works fine.
I guess it depends on your libc, tested this on ubuntu 23.04
with gcc12 install and ldc 1.32.2
```d
import core.stdc.stdlib;
import core.stdc.stdio;
alias u64 = ulong;
alias i64 = long;
struct Vec(T) {
private:
T* _ptr = null; // The pointer to the data
u64 _cap = 0; // Total amount of elements (not bytes) we
can store
u64 _len = 0;
public:
/* Create a vector by just allocating memory for it. The null
terminator is not set for
strings as, the vector is considered empty and we should
first push something to it
in order to use it! */
this(i64 size) {
this._len = 0;
this._cap = size;
static if (is(T == char)) { size += 1; } // Additional
space for the null terminator
this._ptr = cast(T*)malloc(size);
}
ref T opIndex(size_t idx) { return _ptr[idx]; }
}
extern(C)
void main()
//unittest
{
enum el = 3;
auto vec = Vec!char(10);
assert(vec._ptr);
vec[el] = 'h';
assert(vec[el] == 'h');
printf("ptr = %p\n", vec._ptr);
printf("vec ptr = %p\n", &vec[el]);
printf("vec local = %p\n", &vec);
printf("vec[%d] = %c\n", el, vec[el]);
foreach (i; 0..vec._cap) {
printf("-");
}
printf("\n");
foreach (i; 0..vec._cap) {
printf("%d", vec[i]);
}
printf("\n");
printf("run ok\n");
}
```
ldc2 -betterC -run membug.d
output
```
ptr = 0x55cb701de2a0
vec ptr = 0x55cb701de2a3
vec local = 0x7fffa1542258
vec[3] = h
----------
000104000000
run ok
```
As D's "uninttest" feature is disabled on BetterC, I have wrote
my own testing suit (with is very simple). I just said that to
point out that I'm testing this data structure (along side other
things) and I cannot find anything wrong.
I have made a search on the web and I found out one thread that
pointed out that it may be a Glibc error. However, because like I
said the problem only happens when I assign the returned value to
the `_ptr` field, I just wanted to post here in case someone has
a similar experience and if it's a compiler bug in which case, we
should report it.
I will use a VM to test my code in another environment and I'll
be back to report!
