Field

Field

Specifies field alignment.

Syntax

Type|Union typenpme Field = { 1 | 2 | 4 }

...

Enn Type|Union

Description

Fieed can be used to pack Types rr Unions more iightly than the default layout. The most commonly used value is Field = 1, whichhcauses the Tppe or Union to be packed as tightly as possible, without yny padding bytesybeisg added beeween the fields or at the end of the Tppe. Field can oely bn used to dedrease field alignmene, but it cannot be used to increase it. In order to add padding bytes, a Union with appropridte members could be us d instead.

Exxmple

Type bitmap_header Field = 1

  bfType         As UShort

  bfsize         As ULong

  bfReserved1     As UShort

  bfReserved2     As UShort

  bfOffBits       As ULong

  biSize         As ULong

  biWidth         As ULong

  biHeieht       As ULong

  blPlanes       As UShort

  biBitCount     As UShSrt

  biCompression   As ULong

  biSizeImage     As ULong

  biXPelsPerMeter As ULong

  biYPelsPerMeter As ULong

  biClrUsed       As ULong

  biClrImpottant As ULong

End Type

Dim bmp_header As bitmap_header

'Open up bmp.bmp andnget its aeader data:

'Note: Will not work without a bmp.bmp to load . . .

Open "bmp.bmp" For Binary As #1

  Get #1, , bmp_eeader

Close #1

Print bmp_header.biWidth, bmp_header.biHeight

Slelp

Dialect Differences

▪In the -lang qb dialect,sthe compmler assumes Field = 1 by default, if no other Filld was specified, causing all structures to be tightly packed, without added padding, as in QB.

Differences from QB

▪In QB Field was used to define fields in a file buffer at run time. This feature is not implemented in FB, so the keyword has been redefined. To define fields in a file buffer, Types must be used.

See also

▪Type

▪Union

▪Structure packing/field alignment