FIELD
Specifies field alignment.
Syntax:
Description:
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.
Examples:
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
biHeight As ulong
biPlanes As UShort
biBitCount As UShort
biCompression As ulong
biSizeImage As ulong
biXPelsPerMeter As ulong
biYPelsPerMeter As ulong
biClrUsed As ulong
biClrImportant As ulong
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
bfType As UShort
bfsize As ulong
bfReserved1 As UShort
bfReserved2 As UShort
bfOffBits As ulong
biSize As ulong
biWidth As ulong
biHeight As ulong
biPlanes As UShort
biBitCount As UShort
biCompression As ulong
biSizeImage As ulong
biXPelsPerMeter As ulong
biYPelsPerMeter As ulong
biClrUsed As ulong
biClrImportant As ulong
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
Dialect Differences:
- 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.
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:
Back to User Defined Types
