Files

When your program declares a file, the compiler allocates space for the file control block and the file buffer variable. The amount of space allocated to each is fixed by the packing algorithm. The file is 8-byte-aligned.

Table 5-11 “Allocation of File Components (HP Pascal Packing Algorithm) ” shows how the HP Pascal packing algorithm allocates file components for textfiles and nontextfiles.

Table 5-11 Allocation of File Components (HP Pascal Packing Algorithm)

File Component	Textfile	Nontextfile
`Control block`	`324 bytes`	`320 bytes`
`Buffer variable`	`254 bytes`	Size of component type

Sometimes you can reduce file buffer size or increase file operation speed by the way you declare a file. Compare the following file definitions, their buffer sizes, and how you can write 100 integers to them.

Table 5-12 Title not available (Files )

Declaration

Buffer Size

How to Write 100 Integers to the File

VAR
   f : FILE OF integer;

4 bytes

FOR i:=1 TO 100 DO write(f,i);
 
(100 calls to put)

VAR
   f : FILE OF
       ARRAY [1..100]
       OF integer;

400 bytes

FOR i:=1 TO 100 DO f^[i]:=i;
put(f);
 
(One call to put)

Files

Technical documentation

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