The two fragments below compiled and ran as expected using dmd -betterC under Windows.

   string Scrn = "OPO NAM='DspVar1' POS='1,1' VAR=('IntVar1','I');E";


   printf("\nWR_Createtest entered.\n");


   OpStructFstPtr = WR_CreateFormatFile(Scrn);

OpStruct* WR_CreateFormatFile(string parm_Format) {

   import core.stdc.stdio: printf;
   import core.stdc.stdlib: malloc;


   OpStruct* FstOpStructPtr;


   if (parm_Format[0..3] == "OPO"[0..3]) {
      printf("OPO Found.\n");
   } else {
      printf("OPO NOT Found.\n");
   }

   if (parm_Format[$-1..$] == "E"[0..1]) {
      printf("E Found.\n");
   } else {
      printf("E NOT Found.\n");
   }

However, the docs say dynamic arrays are not allowed with betterC, and 'string' implies a dynamic array.
So I expected DMD to complain that my code was invalid.

Any ideas?

On Sunday, 3 November 2024 at 19:00:33 UTC, DLearner wrote:

   string Scrn = "OPO NAM='DspVar1' POS='1,1' VAR=('IntVar1','I');E";


   printf("\nWR_Createtest entered.\n");


   OpStructFstPtr = WR_CreateFormatFile(Scrn);

OpStruct* WR_CreateFormatFile(string parm_Format) {

   import core.stdc.stdio: printf;
   import core.stdc.stdlib: malloc;


   OpStruct* FstOpStructPtr;


   if (parm_Format[0..3] == "OPO"[0..3]) {
      printf("OPO Found.\n");
   } else {
      printf("OPO NOT Found.\n");
   }

   if (parm_Format[$-1..$] == "E"[0..1]) {
      printf("E Found.\n");
   } else {
      printf("E NOT Found.\n");
   }

Id expect this to fail, but nothing I see in yours

string foo="foo";
foo~="bar";

[]'s are both slices and dynamic arrays depending on use, theres a debate about that decision(im of the opinion a [?] should be a dynamic array and clean up the api), but the current situation will only break on appends

On Sunday, 3 November 2024 at 19:47:31 UTC, monkyyy wrote:
[...]

string foo="foo";
foo~="bar";

Surely the line:

   string Scrn = "OPO NAM='DspVar1' POS='1,1' VAR=('IntVar1','I');E";

creates, by the definition of 'string', a dynamic array?

On Sunday, 3 November 2024 at 20:04:19 UTC, DLearner wrote:

string foo="foo";
foo~="bar";

   string Scrn = "OPO NAM='DspVar1' POS='1,1' VAR=('IntVar1','I');E";

By default, a string literal is typed as a dynamic array, but the element count is known at compile time. So all string literals can be implicitly converted to an immutable static array. spec

On Sunday, 3 November 2024 at 19:00:33 UTC, DLearner wrote:

The docs are wrong. Dynamic arrays themselves are allowed; you're just not allowed to perform any operations on them that would cause memory allocation.

This includes, for example,

• concatenating two dynamic arrays with the ~ operator.
• appending to a dynamic array with the ~= operator.
• extending a dynamic array by assigning to its .length property.
• copying a dynamic array using the built-in .dup method.

On Sunday, 3 November 2024 at 20:04:19 UTC, DLearner wrote:

   string Scrn = "OPO NAM='DspVar1' POS='1,1' VAR=('IntVar1','I');E";

I believe thats stored in the binary