CheckSumMappedFile

The CheckSumMappedFile function computes the checksum of the specified image file.

PIMAGE_NT_HEADERS CheckSumMappedFile(
  PVOID BaseAddress,  
  DWORD FileLength,    
  PDWORD HeaderSum,  
  PDWORD CheckSum    
);

Parameters

BaseAddress

[in] Specifies the base address of the mapped file. This value is obtained by calling the MapViewOfFile function.

FileLength

[in] Specifies the length of the file, in bytes.

HeaderSum

[out] Pointer to a variable that receives the original checksum from the image file, or zero if there is an error.

CheckSum

[out] Pointer to the variable that receives the computed checksum.

Return Values

If the function succeeds, the return value is a pointer to the IMAGE_NT_HEADERS structure contained in the mapped image.

If the function fails, the return value is NULL. To retrieve extended error information, call GetLastError.

Remarks

The CheckSumMappedFile function computes a new checksum for the file and returns it in the CheckSum parameter. This function is used by any application that creates or modifies an executable image. Checksums are required for kernel-mode drivers and some system DLLs. The linker computes the original checksum at link time, if you use the appropriate linker switch. For more details, see your linker documentation.

It is recommended that all images have valid checksums. It is the caller's responsibility to place the newly computed checksum into the mapped image and update the on-disk image of the file.

Requirements

  Windows NT/2000: Requires Windows NT 4.0 or later.
  Windows 95/98: Requires Windows 95 or later. Available as a redistributable for Windows 95.
  Header: Declared in Imagehlp.h.
  Library: Use Imagehlp.lib.

See Also

Image Help Library Overview, ImageHlp Functions, IMAGE_NT_HEADERS, MapFileAndCheckSum, MapViewOfFile