program bdemo(output); {demonstrates binary file I/O in GNU Pascal,
using external C routines to help out}
label 9999;
const namelength=100;
type byte=integer(8);
bytefile=packed file of byte;
UNIXfilename=packed array[1..namelength] of char;
var fname:UNIXfilename;
bfile:bytefile;
k,l:integer;
argc:asmname '_p_argc' Integer;
#include "bdemo_ext.h"
procedure printstatus(n:integer);
var x:byte;
begin if testeof(bfile) then writeln('Byte ',n:1,' is EOF')
else begin
bread(bfile,x); writeln('Byte ',n:1,' is ',x:1);
end;
end;
begin if argc=1 then {no file name argument given on command line}
begin writeln('Creating test file btest');
fname:='btest ';
if not testwriteaccess(fname) then
begin writeln('I couldn''t create it!'); goto 9999;
end;
rewrite(bfile,fname);
for k:=-128 to 127 do write(bfile,k);
end
else if argv(1,fname) then
begin k:=1;
while fname[k]<>' ' do k:=k+1;
writeln('Examining file ',fname:k,':');
end else begin writeln('File name too long!');
goto 9999;
end;
if not testreadaccess(fname) then
begin writeln('I couldn''t read it!'); goto 9999;
end;
reset(bfile,fname);
l:=flength(bfile);
writeln('The file is ',l:1,' bytes long');
printstatus(1);
if l>0 then
begin printstatus(2);
if l>1 then
begin movetobyte(bfile,l-2); printstatus(l-1);
end;
movetobyte(bfile,l-1); printstatus(l);
printstatus(l+1);
movetobyte(bfile,l div 2); printstatus(l div 2 + 1);
movetobyte(bfile,1); printstatus(2);
end;
9999:end.
