64 bits integer

64 bits integer

[Luciano Moreira - igLnx]

How can we do to manipulate integer higher than 32 bits in linux ?

Does exist some system call (or another library), that allow us to do 
something like as following ?

int64 x;
x = atoi64("12345678901234567890");

char x[21];
i64toa(x, sizeof(x));

Thanks,

Luciano

Re: 64 bits integer

[mikael-aronsson]

Hi !

You can use the type "long long" to define 64 bit data in gcc, use strtoll()
atoll() to parse a string, and all the *printf functions has support for 64
bit values also.

Mikael

----- Original Message ----- 
From: "Luciano Moreira - igLnx" <lucianolnx@ig.com.br>
To: "linux-c-programming" <linux-c-programming@vger.kernel.org>
Sent: Wednesday, November 10, 2004 2:30 AM
Subject: 64 bits integer


> How can we do to manipulate integer higher than 32 bits in linux ?
>
> Does exist some system call (or another library), that allow us to do
> something like as following ?
>
> int64 x;
> x = atoi64("12345678901234567890");
>
> char x[21];
> i64toa(x, sizeof(x));
>
> Thanks,
>
> Luciano
>
> -
> To unsubscribe from this list: send the line "unsubscribe
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Re: 64 bits integer

[Jan-Benedict Glaw]

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On Tue, 2004-11-09 22:30:57 -0300, Luciano Moreira - igLnx <lucianolnx@ig.com.br>
wrote in message <41916F51.2060102@ig.com.br>:
> How can we do to manipulate integer higher than 32 bits in linux ?
> 
> Does exist some system call (or another library), that allow us to do 
> something like as following ?
> 
> int64 x;
> x = atoi64("12345678901234567890");
> 
> char x[21];
> i64toa(x, sizeof(x));

As pointed out, gcc uses a 64 bit wide integer as long long. If you
really require exactly a 64 bit integer, you'd declare it as uint64_t
(which is from stdint.h). Also, printf() etc will handle it just fine.

If you, however, require integers of at least 64 bit of size (with an
open end), you need to use any of the libraries that offers an
implementation of that. This is beyond the scope of C.  I've just
recently used libgcryp11 for something like that (actually, the large
integers are afterwards used to verify a POS printer's fiscal journal),
but there are other libs for it, too.

MfG, JBG

-- 
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