[fpc-pascal]blockread in a procedure
Hi there,
I'm having trouble using blockread. It was working for... oh, a year... and all of a
sudden it's not working. I'm getting a runtime error 87 in win32/i386 (fpc 1.0.10) and
an error 217 in linux/i386 (fpc 1.0.6). Since I always compile with -gl it tells me
it's failing right at blockread. Here's the code...
const
test_file_name = 'test.txt';
the_source : ansistring = '';
procedure read_source_file;
const
bufsize = 2048;
var
source_file : file;
buf : array [1..bufsize] of char;
count_read : longint; // longint required by blockread
begin
write ('Reading source file.');
assign (source_file, test_file_name);
reset (source_file);
the_source := '';
repeat
blockread (source_file, buf, bufsize, count_read);
the_source := the_source + copy (buf, 1, count_read);
until count_read = 0;
close (source_file);
the_source := the_source + chr(255);
writeln ('Source file successfully read');
end;
begin
read_source_file;
end.
If I get rid of the procedure read_source_file and put its code directly into the main
"begin end." then it works. So for some reason, suddenly it can't stand having
blockread inside a procedure. I haven't touched the procedure or any of the
constants/variables associated with it in a long time, so it's bizarre that it
suddenly decided to fail.
Incidentally, fpc 1.0.10 rpm failed to install on redhat. I struggled with it for a
good hour. Any tips? Does the gz work better than the rpm?
Cheers,
David
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Re: [fpc-pascal]blockread in a procedure
On Sun, 29 Feb 2004, David Emerson wrote:
> Hi there,
>
> I'm having trouble using blockread. It was working for... oh, a year... and all of a
> sudden it's not working. I'm getting a runtime error 87 in win32/i386 (fpc 1.0.10)
> and an error 217 in linux/i386 (fpc 1.0.6). Since I always compile with -gl it tells
> me it's failing right at blockread. Here's the code...
>
>
> const
> test_file_name = 'test.txt';
> the_source : ansistring = '';
>
> procedure read_source_file;
>
> const
> bufsize = 2048;
> var
> source_file : file;
> buf : array [1..bufsize] of char;
> count_read : longint; // longint required by blockread
>
> begin
>
> write ('Reading source file.');
> assign (source_file, test_file_name);
> reset (source_file);
> the_source := '';
> repeat
> blockread (source_file, buf, bufsize, count_read);
> the_source := the_source + copy (buf, 1, count_read);
> until count_read = 0;
> close (source_file);
> the_source := the_source + chr(255);
> writeln ('Source file successfully read');
>
> end;
>
> begin
> read_source_file;
> end.
>
>
> If I get rid of the procedure read_source_file and put its code directly into the
> main
> "begin end." then it works. So for some reason, suddenly it can't stand having
> blockread
> inside a procedure. I haven't touched the procedure or any of the
> constants/variables
> associated with it in a long time, so it's bizarre that it suddenly decided to fail.
did you change the compiler, or one of the compiler flags ?
>
>
> Incidentally, fpc 1.0.10 rpm failed to install on redhat. I struggled with it for a
> good hour. Any tips? Does the gz work better than the rpm?
What error do you get ? What version of rpm do you use ?
If the .rpm fails, the .gz should always install.
Michael.
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Re: [fpc-pascal]blockread in a procedure
On Sun, 29 Feb 2004, David Emerson wrote:
> Hi there,
>
> I'm having trouble using blockread. It was working for... oh, a year... and all of a
> sudden it's not working. I'm getting a runtime error 87 in win32/i386 (fpc 1.0.10)
> and an error 217 in linux/i386 (fpc 1.0.6). Since I always compile with -gl it tells
> me it's failing right at blockread. Here's the code...
>
I tested some things with the current compiler. The error occurs there as
well. It's a stack problem. If you move the 'buf' definition
out of the procedure, I.e. define it as a global var, it works fine.
Assuming you don't want to use a global variable (bad programming practice),
you can also try the following, which works fine as well:
(ansistrings are allocated on the heap, bypassing the stack);
Michael.
program testb;
const
test_file_name = 'test.txt';
the_source : ansistring = '';
const
bufsize = 2048;
procedure read_source_file;
var
source_file : file;
count_read : longint; // longint required by blockread
Buf : AnsiString;
begin
SetLength(Buf,BufSize);
write ('Reading source file.');
assign (source_file, test_file_name);
reset (source_file);
the_source := '';
repeat
blockread (source_file, buf[1], bufsize, count_read);
the_source := the_source + copy (buf, 1, count_read);
until count_read = 0;
close (source_file);
the_source := the_source + chr(255);
writeln ('Source file successfully read');
end;
begin
read_source_file;
end.
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Re: [fpc-pascal]blockread in a procedure (last try!)
On Sun, 29 Feb 2004, David Emerson wrote:
> Hi there,
>
> I'm having trouble using blockread. It was working for... oh, a year... and all of a
> sudden it's not working. I'm getting a runtime error 87 in win32/i386 (fpc 1.0.10)
> and an error 217 in linux/i386 (fpc 1.0.6). Since I always compile with -gl it tells
> me it's failing right at blockread. Here's the code...
>
OK, last try. Not being entirely satisfied with my previous posts, I dug a
little deeper. The strace on linux pointed me to the error.
>
> const
> test_file_name = 'test.txt';
> the_source : ansistring = '';
>
> procedure read_source_file;
>
> const
> bufsize = 2048;
> var
> source_file : file;
> buf : array [1..bufsize] of char;
> count_read : longint; // longint required by blockread
>
> begin
>
> write ('Reading source file.');
> assign (source_file, test_file_name);
> reset (source_file);
This is the culprit. It should read
reset (source_file,1);
By default, the blocksize is 128.
> the_source := '';
> repeat
> blockread (source_file, buf, bufsize, count_read);
With a blocksize of 128, this will try to read 128*2028 (256K)
bytes. My guess is that the OS decides this is outside the
valid stack range, and bails out. Chaning the blocksize to 1 in your
original procedure makes things work just fine.
Remains the question how this ever could have worked.
Michael.
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Re: [fpc-pascal]blockread in a procedure
> On Sun, 29 Feb 2004, David Emerson wrote: > > end. > > > > > > If I get rid of the procedure read_source_file and put its code directly > > into the main "begin end." then it works. So for some reason, suddenly > > it can't stand having blockread inside a procedure. I haven't touched > > the procedure or any of the constants/variables associated with it in a > > long time, so it's bizarre that it suddenly decided to fail. > > did you change the compiler, or one of the compiler flags ? It could be the copy(array of char). It was bugged in 1.9.x too, and got fixed somewhere in august-september (it was pretty much the bug that prevented the compiled twsocket from working). IOW, try 1.9.2 ___ fpc-pascal maillist - [EMAIL PROTECTED] http://lists.freepascal.org/mailman/listinfo/fpc-pascal
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