digitalmars.D.learn - Variables & kind of memory
- Alain De Vos (55/55) Apr 22 2022 I wrote a simple test program:
- Alain De Vos (3/7) Apr 22 2022 BBB: is probably the data-segment.
- Alain De Vos (2/10) Apr 22 2022 Could AAA be the bss-segment ?
- Mike Parker (4/15) Apr 22 2022 Run a dump tool on the generated binary and you can see what goes
- Salih Dincer (23/38) Apr 22 2022 First of all, there is no such thing as a global region in D.
- Mike Parker (2/6) Apr 22 2022 FYI, `static` has no effect at module scope.
- Stanislav Blinov (6/7) Apr 23 2022 Variables declared at module scope, and static variables in
- Alain De Vos (5/12) Apr 23 2022 Maybe i can use gdb to see more info.
- Salih Dincer (23/26) Apr 23 2022 Maybe it'll be helpful. The following output is from another
I wrote a simple test program:
```
import std.stdio:writefln;
int [] GLV=[1,2];
int [2] GLF=[1,2];
static int [] GSLV=[1,2];
static int [2] GSLF=[1,2];
void main(){
writefln("-------------");
writefln("GLV:address :%12x:AAA",&GLV);
writefln("GLF:address :%12x:AAA",&GLF);
writefln("GSLV:address:%12x:AAA",&GSLV);
writefln("GSLF:address:%12x:AAA",&GSLF);
writefln("GLV:ptr :%12x:BBB",GLV.ptr);
writefln("GLF:ptr :%12x:AAA",GLF.ptr);
writefln("GSLV:ptr :%12x:BBB",GSLV.ptr);
writefln("GSLF:ptr :%12x:AAA",GSLF.ptr);
int [] LV=[1,2];
int [2] LF=[1,2];
static int [] SLV=[1,2];
static int [2] SLF=[1,2];
writefln("------------");
writefln(".LV:address :%12x:stack",&LV);
writefln(".LF:address :%12x:stack",&LF);
writefln(".SLV:address:%12x:AAA",&SLV);
writefln(".SLF:address:%12x:AAA",&SLF);
writefln(".LV:ptr :%12x:heap",LV.ptr);
writefln(".LF:ptr :%12x:stack",LF.ptr);
writefln(".SLV:ptr :%12x:BBB",SLV.ptr);
writefln(".SLF:ptr :%12x:AAA",SLF.ptr);
```
Which outputs:
```
-------------
GLV:address : 8002d6120:AAA
GLF:address : 8002d6130:AAA
GSLV:address: 8002d6138:AAA
GSLF:address: 8002d6148:AAA
GLV:ptr : 298808:BBB
GLF:ptr : 8002d6130:AAA
GSLV:ptr : 298810:BBB
GSLF:ptr : 8002d6148:AAA
------------
.LV:address :7fffffffdfd0:stack
.LF:address :7fffffffdfc8:stack
.SLV:address: 8002d6150:AAA
.SLF:address: 8002d6160:AAA
.LV:ptr : 801000000:heap
.LF:ptr :7fffffffdfc8:stack
.SLV:ptr : 298818:BBB
.SLF:ptr : 8002d6160:AAA
```
The output has clearly 4 different kind of memory regions.
I have stack and heap, but don't know what AAA & BBB regions are.
Feel free to elaborate.
Apr 22 2022
On Saturday, 23 April 2022 at 03:41:17 UTC, Alain De Vos wrote:I wrote a simple test program: ``` import std.stdio:writefln; [...]BBB: is probably the data-segment. Remains AAA ?
Apr 22 2022
On Saturday, 23 April 2022 at 04:52:39 UTC, Alain De Vos wrote:On Saturday, 23 April 2022 at 03:41:17 UTC, Alain De Vos wrote:Could AAA be the bss-segment ?I wrote a simple test program: ``` import std.stdio:writefln; [...]BBB: is probably the data-segment. Remains AAA ?
Apr 22 2022
Mike Parker <aldacron gmail.com> On Saturday, 23 April 2022 at 05:01:51 UTC, Alain De Vos wrote:On Saturday, 23 April 2022 at 04:52:39 UTC, Alain De Vos wrote:Run a dump tool on the generated binary and you can see what goes where. And there are probably differences between the three D compilers.On Saturday, 23 April 2022 at 03:41:17 UTC, Alain De Vos wrote:Could AAA be the bss-segment ?I wrote a simple test program: ``` import std.stdio:writefln; [...]BBB: is probably the data-segment. Remains AAA ?
Apr 22 2022
On Saturday, 23 April 2022 at 03:41:17 UTC, Alain De Vos wrote:
I wrote a simple test program:
```d
import std.stdio:writefln;
int [] GLV=[1,2];
int [2] GLF=[1,2];
// paste it ->>
static int [] GSLV=[1,2];
static int [2] GSLF=[1,2];
void main()
{
}
```
First of all, there is no such thing as a global region in D.
Although the addresses are different, we have 2 regions:
* **AAA:** Stack
* **BBB:** Heap
Yes, there are a lot of expressions: ```static, const, immutable,
shared etc.``` But the expressions matters to D compiler. Two
concepts are important to us: the inter-module region and the
```main()``` function where the code starts to run.
Please paste the following into the inter-module region. Turn it
on/off with the toggle (//) sign and see the difference.
```d
//auto data = iota(1024).array; /*
int[] data;
static this() {
data = new int[1024];
} //*/
void main()
{
writefln("%12x, %12x", &data[0], &data[$-1]);
}
```
SDB 79
Apr 22 2022
On Saturday, 23 April 2022 at 03:41:17 UTC, Alain De Vos wrote:int [] GLV=[1,2]; int [2] GLF=[1,2]; static int [] GSLV=[1,2]; static int [2] GSLF=[1,2];FYI, `static` has no effect at module scope.
Apr 22 2022
On Saturday, 23 April 2022 at 03:41:17 UTC, Alain De Vos wrote:Feel free to elaborate.Variables declared at module scope, and static variables in function/aggregate scopes, unless also annotated as `shared` or `__gshared`, are thread-local, therefore are placed in thread-local storage. That's why you see difference in addresses between e.g. &LV and &SLV in `main`.
Apr 23 2022
On Saturday, 23 April 2022 at 10:46:42 UTC, Stanislav Blinov wrote:On Saturday, 23 April 2022 at 03:41:17 UTC, Alain De Vos wrote:Maybe i can use gdb to see more info. This is not a gdb forum but if someone knows the commands to verify the segments/heap/stack ?Feel free to elaborate.Variables declared at module scope, and static variables in function/aggregate scopes, unless also annotated as `shared` or `__gshared`, are thread-local, therefore are placed in thread-local storage. That's why you see difference in addresses between e.g. &LV and &SLV in `main`.
Apr 23 2022
On Saturday, 23 April 2022 at 17:14:22 UTC, Alain De Vos wrote:Maybe i can use gdb to see more info. This is not a gdb forum but if someone knows the commands to verify the segments/heap/stack ?Maybe it'll be helpful. The following output is from another compiler: ``` GLV:address :14eb4a177730:AAA GLF:address :14eb4a177740:AAA GSLV:address:14eb4a177748:AAA GSLF:address:14eb4a177758:AAA GLV:ptr : 4a5488:BBB GLF:ptr :14eb4a177740:AAA GSLV:ptr : 4a5490:BBB GSLF:ptr :14eb4a177758:AAA ------------ .LV:address :7ffeb7c3f228:stack .LF:address :7ffeb7c3f220:stack .SLV:address:14eb4a177760:AAA .SLF:address:14eb4a177770:AAA .LV:ptr :14eb4a077000:heap .LF:ptr :7ffeb7c3f220:stack .SLV:ptr : 4a5498:BBB .SLF:ptr :14eb4a177770:AAA ``` SDB 79
Apr 23 2022