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

...

End Type|Union

Field can be used to pack Types or Unions more tightly than the default layout. The most commonly used value is Field = 1, which causes the Type or Union to be packed as tightly as possible, without any padding bytes being added between the fields or at the end of the Type. Field can only be used to decrease field alignment, but it cannot be used to increase it. In order to add padding bytes, a Union with appropriate members could be used instead.

Type bitmap_header Field = 1
    bfType          As UShort
    bfsize          As UInteger
    bfReserved1     As UShort
    bfReserved2     As UShort
    bfOffBits       As UInteger
    biSize          As UInteger
    biWidth         As UInteger
    biHeight        As UInteger
    biPlanes        As UShort
    biBitCount      As UShort
    biCompression   As UInteger
    biSizeImage     As UInteger
    biXPelsPerMeter As UInteger
    biYPelsPerMeter As UInteger
    biClrUsed       As UInteger
    biClrImportant  As UInteger
End Type

Dim bmp_header As bitmap_header

'Open up bmp.bmp and get its header data:
'Note: Will not work without a bmp.bmp to load . . .
Open "bmp.bmp" For Binary As #1

    Get #1, , bmp_header
    
Close #1

Print bmp_header.biWidth, bmp_header.biHeight

Sleep

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

• Type
  
• Union
  
• Structure packing/field alignment