If the AnsiString variable points to the memory block containing the characters, how is it constructed? How much memory is it reserved for the header?

: If the AnsiString variable points to the memory block containing the characters, how is it constructed? How much memory is it reserved for the header?
:
The header of a nonempty Ansistring consists of the following data:
- 32-bit length indicator
- 32-bit reference count
thus the pointer points to at least 8-bytes of header info. Ansistrings are maintained by using reference counts, which means a code like this:

  String2 := String1;

will not increase its memory usage. Only when String2 is changed, a new string is created, and String1 is duplicated just before applying the change.
This information is taken from the Delphi help files.

: : If the AnsiString variable points to the memory block containing the characters, how is it constructed? How much memory is it reserved for the header?
: :
: The header of a nonempty Ansistring consists of the following data:
: - 32-bit length indicator
: - 32-bit reference count
: thus the pointer points to at least 8-bytes of header info. Ansistrings are maintained by using reference counts, which means a code like this:
:

:   String2 := String1;
: 

: will not increase its memory usage. Only when String2 is changed, a new string is created, and String1 is duplicated just before applying the change.
: This information is taken from the Delphi help files.
:
I tested my Free Pascal version and I realised that the header size variatse between 24 and 32 bytes but never more. Let me just add that I will not modify the data in the AnsiString, I will just use copy it to the new location so I can use it at a nother time. I just have to point the Ansistring pointer to the memory block containing the AsiString. I just have to be certain to copy the whole AnsiSting including the header.

: : : If the AnsiString variable points to the memory block containing the characters, how is it constructed? How much memory is it reserved for the header?
: : :
: : The header of a nonempty Ansistring consists of the following data:
: : - 32-bit length indicator
: : - 32-bit reference count
: : thus the pointer points to at least 8-bytes of header info. Ansistrings are maintained by using reference counts, which means a code like this:
: :

: :   String2 := String1;
: : 

: : will not increase its memory usage. Only when String2 is changed, a new string is created, and String1 is duplicated just before applying the change.
: : This information is taken from the Delphi help files.
: :
: I tested my Free Pascal version and I realised that the header size variatse between 24 and 32 bytes but never more. Let me just add that I will not modify the data in the AnsiString, I will just use copy it to the new location so I can use it at a nother time. I just have to point the Ansistring pointer to the memory block containing the AsiString. I just have to be certain to copy the whole AnsiSting including the header.
:
Delphi features the UniqueString() procedure for this, but you can add a new char and immediately delete it again. This way the string is "changed" and thus copied.

: : : : If the AnsiString variable points to the memory block containing the characters, how is it constructed? How much memory is it reserved for the header?
: : : :
: : : The header of a nonempty Ansistring consists of the following data:
: : : - 32-bit length indicator
: : : - 32-bit reference count
: : : thus the pointer points to at least 8-bytes of header info. Ansistrings are maintained by using reference counts, which means a code like this:
: : :

: : :   String2 := String1;
: : : 

: : : will not increase its memory usage. Only when String2 is changed, a new string is created, and String1 is duplicated just before applying the change.
: : : This information is taken from the Delphi help files.
: : :
: : I tested my Free Pascal version and I realised that the header size variatse between 24 and 32 bytes but never more. Let me just add that I will not modify the data in the AnsiString, I will just use copy it to the new location so I can use it at a nother time. I just have to point the Ansistring pointer to the memory block containing the AsiString. I just have to be certain to copy the whole AnsiSting including the header.
: :
: Delphi features the UniqueString() procedure for this, but you can add a new char and immediately delete it again. This way the string is "changed" and thus copied.
:
Actually I have to copy the AnsiString data to a specific location in the memory. Is there a better way to do this. I want to have ulimited string length.

: : : : : If the AnsiString variable points to the memory block containing the characters, how is it constructed? How much memory is it reserved for the header?
: : : : :
: : : : The header of a nonempty Ansistring consists of the following data:
: : : : - 32-bit length indicator
: : : : - 32-bit reference count
: : : : thus the pointer points to at least 8-bytes of header info. Ansistrings are maintained by using reference counts, which means a code like this:
: : : :

: : : :   String2 := String1;
: : : : 

: : : : will not increase its memory usage. Only when String2 is changed, a new string is created, and String1 is duplicated just before applying the change.
: : : : This information is taken from the Delphi help files.
: : : :
: : : I tested my Free Pascal version and I realised that the header size variatse between 24 and 32 bytes but never more. Let me just add that I will not modify the data in the AnsiString, I will just use copy it to the new location so I can use it at a nother time. I just have to point the Ansistring pointer to the memory block containing the AsiString. I just have to be certain to copy the whole AnsiSting including the header.
: : :
: : Delphi features the UniqueString() procedure for this, but you can add a new char and immediately delete it again. This way the string is "changed" and thus copied.
: :
: Actually I have to copy the AnsiString data to a specific location in the memory. Is there a better way to do this. I want to have ulimited string length.
:
I would suggest that you use a PChar for that. That way you don't have to worry about the header, and only have the string. You can always change it back into an AnsiString in your code.

: : : : : : If the AnsiString variable points to the memory block containing the characters, how is it constructed? How much memory is it reserved for the header?
: : : : : :
: : : : : The header of a nonempty Ansistring consists of the following data:
: : : : : - 32-bit length indicator
: : : : : - 32-bit reference count
: : : : : thus the pointer points to at least 8-bytes of header info. Ansistrings are maintained by using reference counts, which means a code like this:
: : : : :

: : : : :   String2 := String1;
: : : : : 

: : : : : will not increase its memory usage. Only when String2 is changed, a new string is created, and String1 is duplicated just before applying the change.
: : : : : This information is taken from the Delphi help files.
: : : : :
: : : : I tested my Free Pascal version and I realised that the header size variatse between 24 and 32 bytes but never more. Let me just add that I will not modify the data in the AnsiString, I will just use copy it to the new location so I can use it at a nother time. I just have to point the Ansistring pointer to the memory block containing the AsiString. I just have to be certain to copy the whole AnsiSting including the header.
: : : :
: : : Delphi features the UniqueString() procedure for this, but you can add a new char and immediately delete it again. This way the string is "changed" and thus copied.
: : :
: : Actually I have to copy the AnsiString data to a specific location in the memory. Is there a better way to do this. I want to have ulimited string length.
: :
: I would suggest that you use a PChar for that. That way you don't have to worry about the header, and only have the string. You can always change it back into an AnsiString in your code.
:
Can PChar support unlimited string length or will it have problems with more than 255 characters. It shouldn't because it is a null terminated string.

: : : : : : : If the AnsiString variable points to the memory block containing the characters, how is it constructed? How much memory is it reserved for the header?
: : : : : : :
: : : : : : The header of a nonempty Ansistring consists of the following data:
: : : : : : - 32-bit length indicator
: : : : : : - 32-bit reference count
: : : : : : thus the pointer points to at least 8-bytes of header info. Ansistrings are maintained by using reference counts, which means a code like this:
: : : : : :

: : : : : :   String2 := String1;
: : : : : : 

: : : : : : will not increase its memory usage. Only when String2 is changed, a new string is created, and String1 is duplicated just before applying the change.
: : : : : : This information is taken from the Delphi help files.
: : : : : :
: : : : : I tested my Free Pascal version and I realised that the header size variatse between 24 and 32 bytes but never more. Let me just add that I will not modify the data in the AnsiString, I will just use copy it to the new location so I can use it at a nother time. I just have to point the Ansistring pointer to the memory block containing the AsiString. I just have to be certain to copy the whole AnsiSting including the header.
: : : : :
: : : : Delphi features the UniqueString() procedure for this, but you can add a new char and immediately delete it again. This way the string is "changed" and thus copied.
: : : :
: : : Actually I have to copy the AnsiString data to a specific location in the memory. Is there a better way to do this. I want to have ulimited string length.
: : :
: : I would suggest that you use a PChar for that. That way you don't have to worry about the header, and only have the string. You can always change it back into an AnsiString in your code.
: :
: Can PChar support unlimited string length or will it have problems with more than 255 characters. It shouldn't because it is a null terminated string.
:
You answered your own question. The length of a PChar is limited by the block of memory, which is free. Thus if you can allocate 10 GB in a single memory block the PChar can be 10 GB - 1 B (=#0 char) long.

: : : : : : : : If the AnsiString variable points to the memory block containing the characters, how is it constructed? How much memory is it reserved for the header?
: : : : : : : :
: : : : : : : The header of a nonempty Ansistring consists of the following data:
: : : : : : : - 32-bit length indicator
: : : : : : : - 32-bit reference count
: : : : : : : thus the pointer points to at least 8-bytes of header info. Ansistrings are maintained by using reference counts, which means a code like this:
: : : : : : :

: : : : : : :   String2 := String1;
: : : : : : : 

: : : : : : : will not increase its memory usage. Only when String2 is changed, a new string is created, and String1 is duplicated just before applying the change.
: : : : : : : This information is taken from the Delphi help files.
: : : : : : :
: : : : : : I tested my Free Pascal version and I realised that the header size variatse between 24 and 32 bytes but never more. Let me just add that I will not modify the data in the AnsiString, I will just use copy it to the new location so I can use it at a nother time. I just have to point the Ansistring pointer to the memory block containing the AsiString. I just have to be certain to copy the whole AnsiSting including the header.
: : : : : :
: : : : : Delphi features the UniqueString() procedure for this, but you can add a new char and immediately delete it again. This way the string is "changed" and thus copied.
: : : : :
: : : : Actually I have to copy the AnsiString data to a specific location in the memory. Is there a better way to do this. I want to have ulimited string length.
: : : :
: : : I would suggest that you use a PChar for that. That way you don't have to worry about the header, and only have the string. You can always change it back into an AnsiString in your code.
: : :
: : Can PChar support unlimited string length or will it have problems with more than 255 characters. It shouldn't because it is a null terminated string.
: :
: You answered your own question. The length of a PChar is limited by the block of memory, which is free. Thus if you can allocate 10 GB in a single memory block the PChar can be 10 GB - 1 B (=#0 char) long.
:
Thanx a lot.