The PROCMARKHEAD structure is the header for user objects that can be owned by a process without being specific to a desktop and which are “marked” by the process such that the object can easily know which process owns it. Contrast with objects that begin with the smaller PROCOBJHEAD: for these, the only record of ownership is in the HANDLEENTRY.

The PROCMARKHEAD is 0x10 or 0x20 bytes in 32-bit and 64-bit Windows, respectively. Of windowing objects whose names and structural details are known from public symbol files, only the CURSOR begins formally with a PROCMARKHEAD.

Offset (x86) Offset (x64) Definition Versions
0x00 0x00
5.0 and higher
0x08 0x10
ULONG hTaskWow;
5.0 and higher
0x0C 0x18
5.0 and higher