System. getmem, system. freemem-apply for and release memory

If only one pointer is allocated memory, it is the same as new and dispose. The difference is that getmem can apply for multiple consecutive memory blocks.

Example:

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs; Type tform1 = Class (tform) Procedure formcreate (Sender: tobject); end; vaR form1: tform1; implementation {$ R *. DFM} type tmyrec = record {definition structure} Name: String [8]; age: word; end; pmyrec = ^ tmyrec; {definition structure pointer} var PR: pmyrec; procedure tform1.formcreate (Sender: tobject); begin {three structures of memory are allocated at the same time; the three structures in the memory are sequential} getmem (PR, sizeof (tmyrec) * 3); {at this time, PR points to the first structure, with a value assigned to} PR. name: = 'zhang san'; PR. age: = 11; {point PR to the second structure, value assignment} Inc (PR); PR. name: = 'Li si'; PR. age: = 22; {point PR to the third structure, value assignment} Inc (PR); PR. name: = 'wang 5'; PR. age: = 33; {first return to the first structure, and then read} Dec (PR, 2) in sequence; showmessage (format ('% S % d', [pr. name, PR. age]); {Zhang San 11 years old} Inc (PR); showmessage (format ('% S % d', [pr. name, PR. age]); {Li Si 22 years old} Inc (PR); showmessage (format ('% S % d', [pr. name, PR. age]); {Wang Wu 33 years old} {clear the memory of the three structures from the first structure, so that the above three structures are deleted} Dec (PR, 2 ); freemem (PR, sizeof (PR ^) * 3); {sizeof (tmyrec) and sizeof (PR ^) are the same} end; end.
 
   
 

Public Function directory under System Unit