Hi friend
How can I differntiate between OS/2 and windows Bitmap file.
Actually I have a Bmpviewer which works well for all versions of Bmp But when I try to open an OS/2 Bmp it starts performing operations without providing any output or error message.
I don't want to support OS/2 Images But want to display proper message for example "This Bmp is not supported".
So I need to differentiate these two types.

Or more specifically-

In file format specfication I have found that in Bmp width and Height of windows bitmap are signed data but in OS/2 these are unsigned.
So now more specifially I want to differentiate signed and Unsigned data types.
Regards
--Gyan

I dont know about signed and unsigned, but Windows BMP files have this layout:

BITMAPFILEHEADER
BITMAPINFOHEADER, BITMAPV4HEADER or BITMAPV5HEADER
RGBQUAD (if any)
DATA

While OS/2 BMP's have this layout:
BITMAPFILEHEADER
BITMAPCOREHEADER
RGBTRIPLE (if any)
DATA

As you can see, OS/2 bitmaps always have the same kind of second header. First DWORD in this second header is the size. So, after you read BITMAPFILEHEADER from the disk, read a DWORD, and if it's sizeof(BITMAPCOREHEADER) then this file is OS/2.

: Hi friend
: How can I differntiate between OS/2 and windows Bitmap file.
: Actually I have a Bmpviewer which works well for all versions of Bmp But when I try to open an OS/2 Bmp it starts performing operations without providing any output or error message.
: I don't want to support OS/2 Images But want to display proper message for example "This Bmp is not supported".
: So I need to differentiate these two types.
:
: Or more specifically-
:
: In file format specfication I have found that in Bmp width and Height of windows bitmap are signed data but in OS/2 these are unsigned.
: So now more specifially I want to differentiate signed and Unsigned data types.
: Regards
: --Gyan
:
: