According to Berend De Schouwer:

I'd like to read bytes from a file, so I looked at some of the examples. I found an assign(file of byte...). Cool. It doesn't seem to work to great tho... How big does it read? Are you sure its just 1 byte?

Yes. See below for an example program which I just tested to work - with the alpha version gpc-970401.

How big is a byte anyway?

8 bits. :-)

Looking at the examples and the info file, I get confused. Is an integer 16bit or 32bit?

32.

What happens with type byte=0..255;

It will take 4 bytes. :-( Sorry - this is a known bug.

I tried defining them like in the info file (using __short__, etc.) but it doesn't compile. When I use the example's stuff it does compile.

See below for something which does compile.

Hmmm... I am converting some stuff from borland, and some from fpk, so I would like to know how to get 8, 16 and 32 bit signed and unsinged integers. I don't mind doing a search/replace on the source, but I do need to know how big each thing is.

The alpha version gpc-970401 has the following built-in types:

Byte unsigned 8 bits ByteInt signed 8 bits ShortWord unsigned 16 bits ShortInt signed 16 bits Word unsigned 32 bits Integer signed 32 bits LongWord unsigned 64 bits LongInt signed 64 bits

Single = ShortReal 32 Bits Double = Real 64 Bits Extended = LongReal 80 Bits on the PC, maybe 128 elsewhere

However there is one known problem with these types: You cannot `write' or `writeln' them to text file. (Binary files are okay.)

If you

writeln ( a [ 7 ] );

with `a' being an array of bytes, you might get some very strange result because `writeln' outputs the integer consisting of `a [ 7 ]' and the following three bytes.

To work around, cast these types to their base type:

writeln ( Integer ( a [ 7 ] ) );

(The same holds for an `Extended' which you must cast to `Real' in order to `writeln' it.)

AND how to apply them properly to files ;)

I hope the example below helps you. If you want to upgrade to gpc-970401, the URL is

ftp://agnes.dida.physik.uni-essen.de/gnu-pascal/alpha/

Greetings,

Peter

Dipl.-Phys. Peter Gerwinski, Essen, Germany, free physicist and programmer peter.gerwinski@uni-essen.de - http://home.pages.de/~peter.gerwinski/ [970201] maintainer GNU Pascal [970401] - http://home.pages.de/~gnu-pascal/ [970125]

8< ---- test.pas -------------------------------------------------------------

{OK} (* This program will read its own source and output 'OK'. *)

Program Test;

Type ByteInt = __byte__ Integer; Byte = __unsigned__ ByteInt; ByteFile = file of Byte;

Var F: ByteFile; C: Char;

Procedure Assign ( Var T: ByteFile; Name: String );

Var B: BindingType;

begin (* Assign *) unbind ( T ); B:= binding ( T ); B.Name:= Name; bind ( T, B ); B:= binding ( T ); end (* Assign *);

begin Assign ( F, 'test.pas' ); reset ( F ); read ( F, C ); read ( F, C ); write ( C ); read ( F, C ); writeln ( C ); close ( F ); end.