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digitalmars.D.learn - Local variable disappears.

reply SarK0Y <sark0y protonmail.com> writes:
**Hi there, my Dear Fellows.**

i been encountering w/ strange issue..
[ret_emp __emp 
(..)](https://github.com/SarK0Y/DLang/blob/b8e8bb39dda4b5180218998f4700940e218b46f4/source/emp.d#L108)
...
[line 
126](https://github.com/SarK0Y/DLang/blob/b8e8bb39dda4b5180218998f4700940e218b46f4/source/emp.d#L126)
```D
/**********/
   map.name = "name1"; //runs fine
   *map = 0;
   map.prnt;
   simply_print_time ("start tst for __emp");
   map.prnt; // SIGSEGV
/*************/
```
Any ideas???


**|||||||||||||||Thanks a lot in Advance.**
==================
Dec 22 2025
parent reply bauss <jacobbauss gmail.com> writes:
On Monday, 22 December 2025 at 13:53:54 UTC, SarK0Y wrote:

 **Hi there, my Dear Fellows.**

 i been encountering w/ strange issue..
 [ret_emp __emp 
 (..)](https://github.com/SarK0Y/DLang/blob/b8e8bb39dda4b5180218998f4700940e218b46f4/source/emp.d#L108)
 ...
 [line 
 126](https://github.com/SarK0Y/DLang/blob/b8e8bb39dda4b5180218998f4700940e218b46f4/source/emp.d#L126)
 ```D
 /**********/
   map.name = "name1"; //runs fine
   *map = 0;
   map.prnt;
   simply_print_time ("start tst for __emp");
   map.prnt; // SIGSEGV
 /*************/
 ```
 Any ideas???


 **|||||||||||||||Thanks a lot in Advance.**
 ==================


You have this wonderful line nuking your memory:

```
*map = 0;
```
Dec 22 2025
parent reply SarK0Y <sark0y protonmail.com> writes:
On Monday, 22 December 2025 at 16:54:56 UTC, bauss wrote:

 On Monday, 22 December 2025 at 13:53:54 UTC, SarK0Y wrote:

 You have this wonderful line nuking your memory:

 ```
 *map = 0;
 ```


Thanks for Your reply, but i disagree..

```D
   map.name = "name1";
   *map = 0; // if it torpedoes memory
     map.prnt; // then sigsegv must be here
     simply_print_time ("start tst for __emp");
     map.prnt; // but it's here
```
Dec 22 2025
parent reply bauss <jacobbauss gmail.com> writes:
On Monday, 22 December 2025 at 17:03:48 UTC, SarK0Y wrote:

 On Monday, 22 December 2025 at 16:54:56 UTC, bauss wrote:

 On Monday, 22 December 2025 at 13:53:54 UTC, SarK0Y wrote:

 You have this wonderful line nuking your memory:

 ```
 *map = 0;
 ```


 Thanks for Your reply, but i disagree..

 ```D
   map.name = "name1";
   *map = 0; // if it torpedoes memory
     map.prnt; // then sigsegv must be here
     simply_print_time ("start tst for __emp");
     map.prnt; // but it's here
 ```


It is undefined behavior, so it can happen at anytime, anywhere.
Dec 22 2025
next sibling parent SarK0Y <sark0y protonmail.com> writes:
*On Monday, 22 December 2025 at 17:05:16 UTC, bauss wrote:
On Monday, 22 December 2025 at 17:05:16 UTC, bauss wrote:

 On Monday, 22 December 2025 at 17:03:48 UTC, SarK0Y wrote:

 On Monday, 22 December 2025 at 16:54:56 UTC, bauss wrote:

 On Monday, 22 December 2025 at 13:53:54 UTC, SarK0Y wrote:

 You have this wonderful line nuking your memory:

 ```
 *map = 0;
 ```


 Thanks for Your reply, but i disagree..

 ```D
   map.name = "name1";
   *map = 0; // if it torpedoes memory
     map.prnt; // then sigsegv must be here
     simply_print_time ("start tst for __emp");
     map.prnt; // but it's here
 ```


 It is undefined behavior, so it can happen at anytime, anywhere.


**Nice shot == Thanks for Your Help :))**
Dec 22 2025
prev sibling parent reply SarK0Y <sark0y protonmail.com> writes:
On Monday, 22 December 2025 at 17:05:16 UTC, bauss wrote:

 On Monday, 22 December 2025 at 17:03:48 UTC, SarK0Y wrote:

 On Monday, 22 December 2025 at 16:54:56 UTC, bauss wrote:

 On Monday, 22 December 2025 at 13:53:54 UTC, SarK0Y wrote:

 You have this wonderful line nuking your memory:

 ```
 *map = 0;
 ```


 Thanks for Your reply, but i disagree..

 ```D
   map.name = "name1";
   *map = 0; // if it torpedoes memory
     map.prnt; // then sigsegv must be here
     simply_print_time ("start tst for __emp");
     map.prnt; // but it's here
 ```


 It is undefined behavior, so it can happen at anytime, anywhere.


unfortunately, situation been not that simple == seems there is 
problem to initialize class GmpInt properly: i made two funcs to 
create class..
[zz.mk](https://github.com/SarK0Y/DLang/blob/556fefa36e51b46a80de3717d8c495842c36224f/source/class_gmp_z.d#L141)

```D
  static zz* mk () {
         auto __zz = new zz(0);
         auto size_zz = __traits (classInstanceSize, GmpInt);
         auto alloc_zz = cast (zz) malloc (size_zz);
         alloc_zz = __zz.dup;
         alloc_zz.name = "alloc_zz";
         alloc_zz.prnt;
         zz* ret = &alloc_zz;
         ret.prnt;
         return ret;
     }
```
[zz._mk](https://github.com/SarK0Y/DLang/blob/556fefa36e51b46a80de3717d8c495842c36224f/source/class_gmp_z.d#L152)

```D
     static zz* _mk()
     {
         auto __zz = new zz(0);
         zz* ret = &__zz;
         return ret;
     }
```
in short, not sufficient allocation is very culprit here..

PS. variant w/ malloc runs more stable :)
Dec 22 2025
parent SarK0Y <sark0y protonmail.com> writes:
trouble solved :)
Dec 23 2025