[splint-discuss] Confused

[Ralf Wildenhues]

* Rick Bischoff wrote on Thu, Oct 07, 2004 at 02:31:02PM CEST:
> 
> Problem #1
> In my project, I have a series of functions that write "stuff" to a 
> char pointer (cstring).  These functions then return the pointer to 
> where the null terminator currently is on the cstring.  This allows me 
> to, when I am ready to actually collect all of the output together, to 
> do the following:
> 
> /* Sample writing function */
> char* writeSomeStuff(char* buffer) {

char* writeSomeStuff(/*@out@*/ /*@returned@*/ char* buffer);

> *buffer++ = '!';
> *buffer = '\0';
> return buffer;
> }
> 
> /* Sample use of said function */
> void printSomeStuff() {
> char buf[1024];
> char* temp;

/*@dependent@*/ /*@temp@*/ char* temp;

> temp = writeSomeStuff(buf);
> temp = writeSomeStuff1(temp);
> temp = writeSomeStuff2(temp);
> temp = writeSomeStuff3(temp);
> 
> printf("%s\n", temp);
> }

Then these don't produce any more errors.  But you really should not be
using an interface like this, since it makes it extremely difficult and
error-prone to prevent buffer overflows.  Use one that keeps track of
the total size.

> However, if I use the "snprintf" function to write some more 
> complicated things to the output string, splint complains:

If above hints were not enough:  Show complete example code exhibiting
the problem (including the snprintf!).

Regards,
Ralf