container_of: Fail compilation when void * is used as the member_ptr #70
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This is actually a check_types_match problem, as check_types_match(*(void *)0, (int)0) Will succeed because C allows 'void *' to compare against any other pointer. The solution is the same as typecheck.h uses in the kernel: add another pointer '*' to the type. However, this means check_types_match(*(const int *)0, (int)0) Will start failing as the implicit elimination of const is gone. This is actually used by a few container_of users in ccan, and seems desirable. Use a simple solution to constify both sides before adding the extra pointer '*'. Add tests to show that all of these above scenarios work. Signed-off-by: Jason Gunthorpe <[email protected]>
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This is actually a check_types_match problem, as
Will succeed because C allows 'void *' to compare against any other pointer. The solution is the same as typecheck.h uses in the kernel: add another pointer '*' to the type.
However, this means
Will start failing as the implicit elimination of const is gone. This is actually used by a few container_of users in ccan, and seems desirable.
Use a simple solution to constify both sides before adding the extra pointer '*'.
Add tests to show that all of these above scenarios work.