On Friday, 15 September 2023 at 15:27:00 UTC, Vino wrote:
On Friday, 15 September 2023 at 02:25:09 UTC, Joe wrote:
On Thursday, 14 September 2023 at 14:21:09 UTC, Vino wrote:
[...]

A pointer is a type that points to something. It's literally that simple. Every piece of data and code exist somewhere in memory. Every piece of memory has an address. The address is what a pointer contains. Sometimes we want a type that is the address itself rather than a value/number.

[...]

Hi Joe,
Thank you very much for the explanation can you please correct me if my understanding is incorrect
```
byte[] z; // Creates an array of bytes. That is, the compiler will create a pointer to an array of memory and track it's length and deal with memory allocation and all that.
```
If we use the above method then :
The compiler takes care of initilizing the array and free the memory after the usage.
And this is the recommended method.

```
We can use a pointer as an array also, this is the "old school way of creating arrays".
    int qlen = 5;
    int* q = cast(int*)malloc(int.sizeof*qlen);
```     
If we use the above method then :
We need to manual initilize the array.
Ensure that the memory is freed after the usage using try/final block.

By default the memory allocation for arrays in D is based on GC (expect for std.array containers) if we want to reduce/avoid GC then we need to use the old school way of creating the arrays.

In case of using the old school ways then can you guide me what is wrong in my earlier code that I am getting the below error and how do I correct the same.

Error
```
Invalid Name passed: /T&name
double free or corruption (out)
Error: program killed by signal 6
```

Hi All,

At last was able to resolve the issue, but not sure whether this is the reight solution.

Code:
```
import std.stdio: writeln;
import std.exception: enforce;
import std.range: empty;
import std.format: format;

    auto ref testNames(in string[] names) {
      enforce(!empty(names), "Names cannot be Empty or Null");
                        
     import core.stdc.stdlib;
     import std.algorithm: any, canFind;
                
     string[] _names;
     size_t len = 19;
char[] invalid = (cast(char*)malloc(char.sizeof * len))[0..len];
     invalid[0 ..len] = 0; //Array Initlization
                        
     try {
           version(Posix) {
invalid = ['\'','\"',':',';','*','&','/','[',']','-','+','$','#','<','>','{','}','(',')'];
          }

          foreach(i; names.dup) {
          auto result = i.any!(a => invalid.canFind(a));
if(result) { throw new Exception("Invalid Name passed: %s".format(i)); }
          else {_names = names.dup; return _names; }
          }
        } catch(Exception e) { writeln(e.msg);  }
finally { invalid = null; free(invalid.ptr); } // added invalid = null resolved the issue
         return _names;
    }

    void main () {
        writeln(testNames(["/T&name"]));
    }

From,
Vino

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