What does this code do?

[cman]

I found this macro in the Linux source, can anyone help me decipher
what it is doing?

#define LIST_HEAD_INIT(name) { &(name), &(name) }

cman

 

[Richard Bos]

I found this macro in the Linux source, can anyone help me decipher
what it is doing?

#define LIST_HEAD_INIT(name) { &(name), &(name) }

Nothing, /per se/. How is it called?

Richard

 

[cman]

Nothing, /per se/. How is it called?

Richard

It is called as LIST_HEAD_INIT(inode_used) - where inode_used is of
type struct inode etc.

cman

 

[Richard Bos]

It is called as LIST_HEAD_INIT(inode_used) - where inode_used is of
type struct inode etc.

A single object? No side effects? Not as part of another line? Then it
does exactly nothing.

Richard

 

[user923005]

I found this macro in the Linux source, can anyone help me decipher
what it is doing?

#define LIST_HEAD_INIT(name) { &(name), &(name) }

Many compilers will show you the result of the preprocessor output if
you choose a compiler flag to allow it.
For instance, with MS VC++ it is /EP and with gcc, you can run the
preprocessor on its own.

 

[mark_bluemel]

A single object? No side effects? Not as part of another line? Then it
does exactly nothing.

The OP seems not to have done enough research...
Here's an example:-
struct address_space swapper_space = {
- .page_tree = RADIX_TREE_INIT(GFP_ATOMIC),
- .page_lock = RW_LOCK_UNLOCKED,
- .clean_pages = LIST_HEAD_INIT(swapper_space.clean_pages),
- .dirty_pages = LIST_HEAD_INIT(swapper_space.dirty_pages),
- .io_pages = LIST_HEAD_INIT(swapper_space.io_pages),
- .locked_pages = LIST_HEAD_INIT(swapper_space.locked_pages),
[etc...]

It looks to me to be an initializer for a circular list.

 

[mark_bluemel]

I found this macro in the Linux source, can anyone help me decipher
what it is doing?

#define LIST_HEAD_INIT(name) { &(name), &(name) }

cman

Google very quickly gave me http://www.thescripts.com/forum/thread220697.html

 

[mark_bluemel]

Google very quickly gave mehttp://www.thescripts.com/forum/thread220697.html

And shortly after that I found http://isis.poly.edu/kulesh/stuff/src/klist/