The third compiler option I'd like to discuss regulates the alignment of fields in Delphi record and class types. It can be set to the following values: Off, Byte, Word, Double Word, and Quad Word. Settings are a bit misleading, as the first two values actually result in the same behavior.
You can use compiler directives {$ALIGN 1} , {$ALIGN 2}, {$ALIGN 4}, and {$ALIGN 8} to change record field alignment in code, or equivalent short forms {$A1}, {$A2}, {$A4}, and {$A8}. There are also two directives which exist only for backward compatibility. {$A+} means the same as {$A8} (which is also a default for new programs) and {$A-} is the same as {$A1}.
Field alignment controls exactly how fields in records and classes are ...
