Some progrtamming questions
lazarus / 8-Other

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Rave · 2009-05-03 21:14

Hello. I would to ask how to:

1. Handle "file", not "file of", just "file" files? I mean when I
expecting data sequence string-integer-string could I put
read(str)
read(int)
read(str)
and i'll got the same data as I saved before?
2. Let's say that I have name of procedure or function as string. How
to get procedure address of that function/proc and then execute it
(normally I will use proc(parameters), but how with calling by proc
address?). I do not want to checking it in long if..else, because
procedures will be lot.

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Leledumbo · 2009-05-04 03:21

QuoteI mean when I expecting data sequence string-integer-string could
I put ... and i'll got the same data as I saved before?No. Untyped
files should be handled specially using BlockRead / BlockWrite
routines. For instance, if you want to read it as string-integer-
string, you can do:
Code: [Select]var
  InputFile: File;
  Buffer,String1,String2: String;
  AnInteger: Integer;
... // do Assign & Reset
SetLength(String1,String1Len); // You MUST know the length
BlockRead(InputFile,String1,String1Len);
BlockRead(InputFile,AnInteger,SizeOf(Integer);
SetLength(String2,String2Len); // Again, you MUST know the length
BlockRead(InputFile,String2,String2Len);
... // Close, and you have the data now (actually, you already have
after every BlockRead call

QuoteLet's say that I have name of procedure or function as string.
How to get procedure address of that function/proc and then execute
itIf it resides in a dynamic library, then GetProcAddress should
suffice. You can then typecast it to a compatible procedural type and
assign it to a variable. Execute it as how you would execute a
procedure from a procedural variable.

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Rave · 2009-05-04 06:43

Quote from: Leledumbo on May 04, 2009, 05:21:50 amQuoteI mean when I
expecting data sequence string-integer-string could I put ... and i'll
got the same data as I saved before?No. Untyped files should be
handled specially using BlockRead / BlockWrite routines. For instance,
if you want to read it as string-integer-string, you can do:
[/quote]
So I can read first length as integer then string itself.
Quote from: Leledumbo on May 04, 2009, 05:21:50 amQuoteLet's say that
I have name of procedure or function as string. How to get procedure
address of that function/proc and then execute itIf it resides in a
dynamic library, then GetProcAddress should suffice. You can then
typecast it to a compatible procedural type and assign it to a
variable. Execute it as how you would execute a procedure from a
procedural variable.
Nope. The procedure will exist only in main app code. This is not
right thing for creating a library that will be used only in one
application? How to execute proc from procedure viariable?