How to call a function in another unit?

I renamed search.pas to Function.pas to make the name more general.

Below in the code section is procedure FindOCRString(); which is in the main program, Unti1.  Below that is the entire program Functions;

This is how I make the function call from Unit1 (main program):  posBegin := PosInFile(Str, FileName);

It throws compile error: Undeclared Identifier: "PosInFile".

Spelling seems to be correct.

I don't understand why?  

Thanks.

Uni1.pas
---------
procedure FindOCRString();
var
 Str : string;
 i, posBegin, posEnd : integer;
begin
  for i:=1 to NoDocsInBatch do begin
    Str:='#/';
    FileName := 'z:\TEMP\0000000051.tif.txt';
    posBegin := PosInFile(Str, FileName);
    Str:='/#';
    posEnd := PosInFile(Str, FileName);
    List := TStringList.Create;
    try
      List.Delimiter := '|';
      List.DelimitedText := OCRString;
      VendorNo := List[0];
      InvoiceNo := List[1];
      InvoiceDate := List[2];
      PO := List[3];
      SubTotal := List[4];
      Tax := List[5];
      Shipping := List[6];
      Deposit := List[7];
      BalanceDue := List[8];
      //ShowMessage(VendorNo+'|'+InvoiceNo+'|'+InvoiceDate+'|'+ PO+'|'+SubTotal+'|'+Tax+'|'+Shipping+'|'+Deposit+'|'+BalanceDue);
    finally
      List.Free;
    end;
  end;
end;
 
 
unit Functions;
 
interface
 
uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, DB, mySQLDirectQuery, mySQLDbTables;
 
const
  MAXFILESIZE = 16383;
 
var
  OCRString: string;
  posBegin, posEnd: Integer;
  Buffer: array[0..MAXFILESIZE] of char;
  FileName, Str, ImageName: string;
  BufPtr, BufEnd: integer;
  F: file;
  Index: integer;
  Increment: integer;
  c: char;
  VendorNo, InvoiceNo, InvoiceDate, PO, Tax, Shipping, SubTotal, Deposit, BalanceDue: string;
 
  List: TStringList;
 
implementation
 
function PosInFile(Str, FileName: string): integer;
  function NextChar: char;
  begin
    if BufPtr >= BufEnd then
    begin
      BlockRead(F, Buffer, MAXFILESIZE, BufEnd);
       //ShowMessage('Char Read: '+IntToStr(BufEnd));
      BufPtr := 0;
      Application.ProcessMessages;
    end;
    Result := Buffer[BufPtr];
    Inc(BufPtr);
  end;
 
begin
  Result := -1;
  AssignFile(F, FileName);
  Reset(F, 1);
  BufPtr := 0;
  BufEnd := 0;
  Index := 0;
  Increment := 1;
  repeat
    c := NextChar;
    if c = Str[Increment] then
      Inc(Increment)
    else
    begin
      Inc(Index, Increment);
      Increment := 1;
    end;
    if Increment = (Length(Str) + 1) then
    begin
      Result := Index;
      break;
    end;
  until BufEnd = 0;
 
end;
 
function RightStr
    (Const Str: String; Size: Word): String;
begin
  if Size > Length(Str) then Size := Length(Str) ;
  RightStr := Copy(Str, Length(Str)-Size+1, Size)
end;
 
function MidStr
    (Const Str: String; From, Size: Word): String;
begin
  MidStr := Copy(Str, From, Size)
end;
 
function LeftStr
    (Const Str: String; Size: Word): String;
begin
  LeftStr := Copy(Str, 1, Size)
end;
 
end.

Select allOpen in new window

OMY!!! So easy.  Sorry I asked.

Up points to give credit due to all responders.  Gave few extra points to tankergoblin because he was very kind in supplying a code sample.  If anyone objects, please contact me.

Thanks to all.

dear bokist
i tried your way, but I got the following error
"This form of method call only allowed for class methods"

what should I do, I have a function "SendEmail" that will be used in all my units.pas and I want to write that function one time and call it from all the units
thank you

@Amanda77,
For openers, start your own question. ;-)
Do so and I will supply an answer. ;-)