> From: Christopher Schultz [mailto:[email protected]]
> Subject: Re: [OT] JNI problem
>
> I saw the same thing at first glance, but then I looked-up the sizeof()
> operator and it seems that sizeof /can/ return the number of bytes in
> an array in C99
Minor correction: the operator is sizeof, not sizeof() - it is not a function.
The parentheses one often sees with sizeof are either unnecessary (when used
around a variable name) or a *cast* operator, when used with a type. The
sizeof operator always returns the number of bytes occupied by the type of the
operand, which is the declared size, not any associated dynamically allocated
size. For example:
char array[6];
char * ptr;
struct string {
int len;
char body[];
};
struct string sptr = malloc(sizeof (struct string) + 8);
sizeof array returns 6
sizeof ptr returns 4 or 8, depending on platform
sizeof (struct string) returns 4 (usually; sometimes 8) - the length of the int
sizeof sptr returns 4 or 8, depending on platform
sizeof *sptr returns the same as sizeof (struct string)
- Chuck
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