[splint-discuss] Splint usage help

[Brian Quinlan]

On Sat, 2009-04-18 at 06:38 -0700, Marcus Martin wrote:
> <Please ignore the first message, this one is in plain text.>
> 
> 
> I
> am a new splint user and am having some difficutly with the
> annotations. I read the documentation and looked at the examples and
> still have some trouble. Can someone please help me get started?
> 
> I have the source code line:
> const char *subCmds[] = { "-file", "-stream", NULL }; 
> 
Hi Marcus,
Try the following:

typedef /*@null@*/ const char *StringListElement;
StringListElement subCmds[] = { "-file", "-stream", NULL };

The basic problem is that splint (reasonably) assumes const char* is
non-null. In this case, you need to change this assumption by using the
the /*@null@*/ annotation. Adding it directly to your line doesn't work.
I think this is because this tells splint the array, rather than each
array element, can be null. There might be a way of achieving the same
effect without the two line hack, but I don't see it myself.

Bye,
Brian


> This
> array needs to have the last element be NULL so when used a parameter
> in a method, the method knows when to stop reading the array. Splint
> produces the following errors.
> 
> test.c:94:68: Index of possibly null pointer subCmds: subCmds
>   A possibly null pointer is dereferenced.  Value is either the result of a
>   function which may return null (in which case, code should check it is not
>   null), or a global, parameter or structure field declared with the null
>   qualifier. (Use -nullderef to inhibit warning)
>    test.c:94:27: Storage subCmds may become null
> test.c:94:61: Local subCmds[2] initialized to null value: subCmds[2] = NULL
>   A reference with no null annotation is assigned or initialized to NULL.  Use
>   /*@null@*/ to declare the reference as a possibly null pointer. (Use
>   -nullassign to inhibit warning)
> 
> After reading the warnings I tried changing the source line in the following ways, none of which worked for me.
> 
> /*@-nullderef@*/ const char *subCmds[] = { "-file", "-stream", NULL };  /*@=nullderef@*/ 
> /*@-nullassign@*/ const char *subCmds[] = { "-file", "-stream", NULL };  /*@=nullassign@*/
> const char *subCmds[] = { "-file", "-stream", /*@null@*/  NULL }; 
> 
> The
> second problem I encountered is that splint wants me to annotate the
> header files of exeternal packages I call to indicate out parameters
> and parameters that can be NULL. Since I don't own that source code,I
> really don't want to change it. How do I indicate to splint where I
> invoked the method that my parameters are correct and the method is
> used correctly.
> 
> The third issue is that I am creating a shared
> library that  implements the interface. At no place in my code base
> will I call these public interface methods. How can I tell splint that
> these methods are exported and not called directly, but that is okay.
> 
> Can
> someone tell me what I am doing wrong? Once I understand these three
> problems, I should be able to fix the rest of my module.
> 
> Marcus
> 
> 
>       
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