Re: sizeof()'s strange behviour

Keith Thompson wrote:
Richard Heathfield <rjh@xxxxxxxxxxxxxxx> writes:
arnuld said:
[...]
printf("sizeof(%s): %d\n", s, sizeof(s));
...so we'd expect this to print 16 in place of the second % format
specifier. Note that your printf is misleading. It will print:

sizeof(Saurabh Nirkhey): 16

but in fact it's sizeof s that is 16.
[...]

Furthermore, "%d" causes printf to expect an int argument, but
sizeof(s) is of type size_t. It's likely to happen to work on systems
where int and size_t are the same size, but the right way is (with a
couple of other tweaks):

printf("sizeof s: %d\n", (int)sizeof s);

Richard mentioned this already in his post.

I'd add that C99 provides the 'z' format modifier for size_t values:

printf("sizeof s: %zd\n", sizeof s);

....although if your code isn't C99 for other reasons, this is hardly a
great reason to break C90 compatibility.
.

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