std::size_t

[Philipp Kraus]

Hello,

is there a signed datatype like the unsigned std::size_t? I think
std:trdiff_t is for pointer arithmetics. I need a type with the same
size but like a signed datatype.

Thanks

Phil

 

[Ian Collins]

Hello,

is there a signed datatype like the unsigned std::size_t? I think
std:trdiff_t is for pointer arithmetics. I need a type with the same
size but like a signed datatype.

POSIX defines ssize_t, other systems may also have it. Other wise
define your own.

 

[Juha Nieminen]

is there a signed datatype like the unsigned std::size_t? I think
std:trdiff_t is for pointer arithmetics. I need a type with the same
size but like a signed datatype.

Not an answer to your question, but an additional question (related
to it):

Does the standard allow sizeof(std:trdiff_t) to be different from
sizeof(std::size_t)?

 

[Bo Persson]

Not an answer to your question, but an additional question (related
to it):

Does the standard allow sizeof(std:trdiff_t) to be different from
sizeof(std::size_t)?

The standard doesn't say anything about that, except that they
shouldn't be larger than sizeof(unsigned long) unless specifically
needed.

If it isn't forbidden, it's probably allowed.



Bo Persson

 

[Philipp Kraus]

POSIX defines ssize_t, other systems may also have it. Other wise
define your own.

Thanks for that answer. I know that POSIX defines this, but my code is
for cross-plattform, so I can't use the POSIX definition. I think I
will define my own type

Phil

 

[Michael Doubez]

Thanks for that answer. I know that POSIX defines this, but my code is
for cross-plattform, so I can't use the POSIX definition. I think I
will define my own type

If your compilers supports some C++0x features, you can define:

typedef std::make_signed<size_t>::type ssize_t;

Or roll your own make_signed<>.

 

[SaticCaster]

Article "About size_t and ptrdiff_t" - http://www.viva64.com/en/a/0050/