Meaning of preprocessing in Windows drivers

 

# Pragma code_seg ("page ")
This part of code is put into the paging memory for running.

# Pragma code_seg ()
Set the code segment as the default code segment

# Pragma code_seg ("init ")
Loaded to the init memory area. After loading, you can exit the memory.

From: http://blog.csdn.net/whatday/article/details/7100855

 

Windows requires that some virtual memory can be exchanged to files. Such memory is calledPaging memory

Some virtual memory will never be switched to files.Non-Paging memory

# Define pagedcode code_seg ("page"); // paging memory

# Define lockedcode code_seg (); // non-Paging

# Define initcode code_seg ("init ");

 

# Define pageddata data_seg ("page ");

# Define lockeddata data_seg ();

# Define initdata data_seg ("init ");

 

Example:

If you load a function into the paging memory, the following functions are available:

# Pragma pagedcode

Void fun ()

{

Paged_code (); // do something

}

Note:Paged_code () is a macro provided by DDK and takes effect only in the check version. It checks this function.
Indicates whether the number of interrupted requests is lower than dispatch_leval. If the number is equal to or higher than the level of the interrupted request, an asserted is generated. When the program runs on the dispatch_level (including the current layer), the program can only use non-Paging memory; otherwise, the blue screen will crash.

 

If you load a function into non-Paging memory, the following functions are available:

# Pragma lockedcode

Void fun ()

{

}

A routine needs to load the memory during initialization and can be detached from the memory. For example, in DriverEntry mode, DriverEntry will be large and occupy a large amount of space. In order to save memory, need to detach from memory in time

# Pragma initcode

Ntstatus DriverEntry (

In pdriver_object pdriverobject,

In punicode_string registerpath)

{// Do something}

From: http://blog.chinaunix.net/uid-24504987-id-161192.html