derefrencing pointer to incomplete type error

aliasghar · 09-15-2009, 04:02 PM

I 'm writing a code to traverse all allocated slabs. First I traverse cache list through "cache_chain". my code is:

Code:

struct list_head cache_chain, *p;
list_for_each(p, &cache_chain){
    kmem_cache_t *cachep=list_entry(p, struct kmem_cache_t, next); 
    ...
}

but when compiling I receive following errors:
error: dereferencing pointer to incomplete type
error: invalid use of incomplete typedef 'keme_cache_t'
what should I do?

bithub · 09-15-2009, 04:12 PM

Quote:

error: invalid use of incomplete typedef 'keme_cache_t'

Is that bolded part just a typo? The error lists keme_cache_t, but your code has kmem_cache_t.

If it is just a typo, then it's appears to be a problem where you typedef'd a type, but didn't include the header file for that type.

aliasghar · 09-17-2009, 04:06 AM

yes, that's a typo.
I think the error is because of one of these two reasons:
1. the header file for kmem_cache_t is not included: I tried to find the header file but I couldn't.
2. cache_chain is not initialized. this reason is more logical for me, but I don't know how to initialize it. can you help me, please?
and, thanks for first reply.

MK27 · 09-17-2009, 09:31 AM

Quote:

Originally Posted by aliasghar

1. the header file for kmem_cache_t is not included: I tried to find the header file but I couldn't.

Because it doesn't exist. I grepped thru the kernel headers and /usr/include. It is not referred to anywhere:

Then I googled this

[PATCH] Remove the deprecated "kmem_cache_t" typedef from slab.h.

apparently kmem_cache_t used to be in slab.h (a kernel header) but is no longer used in the kernel tree so has been depreciated right out.

I think the original typdef is in that post tho, so you could just paste it in.

09-15-2009, 04:02 PM	#1
aliasghar Registered User Join Date: Sep 2009 Posts: 5	derefrencing pointer to incomplete type error I 'm writing a code to traverse all allocated slabs. First I traverse cache list through "cache_chain". my code is: Code: struct list_head cache_chain, p; list_for_each(p, &cache_chain){ kmem_cache_t cachep=list_entry(p, struct kmem_cache_t, next); ... } but when compiling I receive following errors: error: dereferencing pointer to incomplete type error: invalid use of incomplete typedef 'keme_cache_t' what should I do?
aliasghar is offline

09-17-2009, 04:06 AM	#3
aliasghar Registered User Join Date: Sep 2009 Posts: 5	yes, that's a typo. I think the error is because of one of these two reasons: 1. the header file for kmem_cache_t is not included: I tried to find the header file but I couldn't. 2. cache_chain is not initialized. this reason is more logical for me, but I don't know how to initialize it. can you help me, please? and, thanks for first reply.
aliasghar is offline

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