Hi,
I'm new to splint and I would like to remove some warnings like
"fresh storage bla not released before return" if the function is
returning a pointer to a static buffer, I used following (test) code:
--
/*@exposed@*/ static char *func(char *s)
{
static char sbuf[512];
sprintf(sbuf, "[TEST] %s", s);
return sbuf;
}
int main()
{
char *p;
char *s;
p = func("alpha");
s = func("beta");
if (strcmp(p, "[TEST] alpha") == 0)
printf("NOTREACHED\n");
else
printf("Result: '%s'\n", p);
return 1;
}
--
Splint 3.0.1.4 --- 20 Jan 2002
Finished checking --- no warnings
--
Ok now I got the warnings gone, but splint doesn't seem to understand
that after "s = func("beta");" the contents of *p are also changed.
Is it possible to let splint detect this, and if so, how?
Then some slightly different code: I replace sprintf with strcpy, then I get:
--
stor2.c: (in function func)
stor2.c:4:9: Parameter 1 (sbuf) to function strcpy is declared unique but may
be aliased externally by parameter 2 (s)
A unique or only parameter may be aliased by some other parameter or visible
global. (Use -mayaliasunique to inhibit warning)
--
So I try to correct this by using /*@unique@*/, it then doesn't like the observer
value I passed:
--
stor2.c:8:5: Function main declared without parameter list
A function declaration does not have a parameter list. (Use -noparams to
inhibit warning)
stor2.c: (in function main)
stor2.c:12:11: Observer storage passed as unique param: func ("alpha")
Observer storage is transferred to a non-observer reference. (Use
-observertrans to inhibit warning)
stor2.c:12:11: Storage becomes observer
stor2.c:13:11: Observer storage passed as unique param: func ("beta")
stor2.c:13:11: Storage becomes observer
--
Ok, that's correct, so I change it to /*@unique@*/ /*@observer@*/ since
the contents aren't changed (I hope that's the right use of "observer").
So in the end I get the following code:
--
/*@exposed@*/ static char *func(char /*@unique@*/ /*@observer@*/ *s)
{
static char sbuf[512];
strcpy(sbuf, s);
return sbuf;
}
int main()
{
char *p;
char *s;
p = func("alpha");
s = func("beta");
if (strcmp(p, "alpha") == 0)
printf("NOTREACHED\n");
else
printf("Result: '%s'\n", p);
return 1;
}
--
Splint doesn't give any warnings, ok...
But if I replace:
s = func("beta");
with:
s = func(p);
splint also doesn't complain...
or did I misinterpretate the word "unique" and does
it only check if the parameters are unique, not unique
to other vars in a function.
Thanks,
Syzop.
