Question about strings in files

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Septe:
I typed in an example from a tutorial that I dug up online. It was an example on writing files to the disk. I ran into a message stating that I can't use reference counted types in files. Looking through the documentation, I forced the program to use short strings with {$H-}. Now my question or more accurately a confirmation. I noticed that my data file was 768 bytes. Since I had three strings being written to the file, I take it that fpc pads the string (being 256 bytes in size) with something, correct? If I wanted to just print to the length of the strings, is there something that I can look at to research this?

Thanks,
Septe

Leledumbo:

--- Quote from: Septe on April 23, 2015, 04:38:01 pm ---I noticed that my data file was 768 bytes. Since I had three strings being written to the file, I take it that fpc pads the string (being 256 bytes in size) with something, correct?

--- End quote ---
Nope, 768 / 3 = 256, the correct size of each short string without explicit length. Read the last paragraph in the docs.

rvk:

--- Quote from: Septe on April 23, 2015, 04:38:01 pm ---... I take it that fpc pads the string (being 256 bytes in size) with something, correct?
--- End quote ---
You probably used a typed file (of type string). In that case FPC doesn't write the string to your file but a record containing the string. And that record is of a fixed size. This could be useful if you want to read the 1234'th string in a file of 9999 strings. With a textfile you would need to read the whole file and count the strings read until you get to 1234'th string.

--- Quote from: Septe on April 23, 2015, 04:38:01 pm ---If I wanted to just print to the length of the strings, is there something that I can look at to research this?

--- End quote ---
If you want to write the strings with just the length of the strings you probably want a text-file. Use Filevar: TextFile for that. (and use Writeln(Filevar, Str); to write to that file).

You can read more about that in the wiki:
http://wiki.freepascal.org/File_Handling_In_Pascal
http://wiki.lazarus.freepascal.org/File

Septe:
In this situation, it was a file of StudentRecord of which contains String. Leledumbo answered my question. Thanks Leledumbo.

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