Typecaste Question

[John Smith]

Hi,

I am using solaris 8. I can't figure out how to copy strings:

The following are defined in a .h file:
-----------------------------------------------------------------------
typedef struct string_type {
union u {
char some_val[32];
int some_val2;
} _u;
}STYPE;

#define DecStr(s_variable) extern STYPE *s_variable

-------------------------------------------------------------------------

This is a simplified version of what I am trying to do:


DecStr(MyId);

unsigned char octet[13];

octet[ 0] = (unsigned char)12;
octet[ 1] = (unsigned char)13;
octet[ 2] = (unsigned char)14;
octet[ 3] = (unsigned char)15;
octet[ 4] = (unsigned char)00;
octet[ 5] = 0x0;

MyId=(STYPE *)octet;


The problem is that MyId doesn't get the values assigned from octet?

Can anyone help me how to caste this string?

Thanks!

[David Schwartz]

"John Smith" <John_Smith273@cox.net> wrote in message
news:jjiQa.950$Ze.636@fed1read03...

> I am using solaris 8. I can't figure out how to copy strings:

> The following are defined in a .h file:
> -----------------------------------------------------------------------
> typedef struct string_type {
> union u {
> char some_val[32];
> int some_val2;
> } _u;
> }STYPE;

> #define DecStr(s_variable) extern STYPE *s_variable

This declares a pointer to an STYPE, not an actual STYPE.

> This is a simplified version of what I am trying to do:
>
>
> DecStr(MyId);

This makes MyId a pointer to an STYPE.

> unsigned char octet[13];
>
> octet[ 0] = (unsigned char)12;
> octet[ 1] = (unsigned char)13;
> octet[ 2] = (unsigned char)14;
> octet[ 3] = (unsigned char)15;
> octet[ 4] = (unsigned char)00;
> octet[ 5] = 0x0;
>
> MyId=(STYPE *)octet;

Umm, 'octet' is NOT an STYPE.

> The problem is that MyId doesn't get the values assigned from octet?

How did you determine this?

> Can anyone help me how to caste this string?

Can you be more precise about what you're trying to do? If you're trying
to *copy* a string, you need to use some sort of copying function (like
'strcpy').

DS

[John Smith]

"David Schwartz" <davids@webmaster.com> wrote in message
news:beshq2$473$1@nntp.webmaster.com...

>
> "John Smith" <John_Smith273@cox.net> wrote in message
> news:jjiQa.950$Ze.636@fed1read03...
>

> > I am using solaris 8. I can't figure out how to copy strings:

>

> > The following are defined in a .h file:
> > -----------------------------------------------------------------------
> > typedef struct string_type {
> > union u {
> > char some_val[32];
> > int some_val2;
> > } _u;
> > }STYPE;

>

> > #define DecStr(s_variable) extern STYPE *s_variable

>
> This declares a pointer to an STYPE, not an actual STYPE.
>

> > This is a simplified version of what I am trying to do:
> >
> >
> > DecStr(MyId);

>
> This makes MyId a pointer to an STYPE.
>

> > unsigned char octet[13];
> >
> > octet[ 0] = (unsigned char)12;
> > octet[ 1] = (unsigned char)13;
> > octet[ 2] = (unsigned char)14;
> > octet[ 3] = (unsigned char)15;
> > octet[ 4] = (unsigned char)00;
> > octet[ 5] = 0x0;
> >
> > MyId=(STYPE *)octet;

>
> Umm, 'octet' is NOT an STYPE.
>

> > The problem is that MyId doesn't get the values assigned from octet?

>
> How did you determine this?
>

> > Can anyone help me how to caste this string?

>
> Can you be more precise about what you're trying to do? If you're

trying

> to *copy* a string, you need to use some sort of copying function (like
> 'strcpy').
>
> DS

Thanks for your kind response.

1) I am trying to copy the string octet into MyId. The framwork I am working
in has a function called DecStrCopy (STYPE *destString, STYPE *srcString).
So somehow I have to cast octet to STYPE.

2) Furthermore, I was wondering if I can completely take octet out of the
picture. I should be able to just use MyId instead of octet above.

Can I do something or a variation like:

*MyId[0] = (unsigned char *)12;
*MyId[1] = (unsigned char *)13;

So on an so forth.

[David Schwartz]

"John Smith" <John_Smith273@cox.net> wrote in message
news:RxnQa.1010$Ze.642@fed1read03...

> Thanks for your kind response.

> 1) I am trying to copy the string octet into MyId. The framwork I am

working

> in has a function called DecStrCopy (STYPE *destString, STYPE *srcString).
> So somehow I have to cast octet to STYPE.

Okay, that's impossible. You can't copy data into a pointer, there's no
room.

> 2) Furthermore, I was wondering if I can completely take octet out of the
> picture. I should be able to just use MyId instead of octet above.
>
> Can I do something or a variation like:
>
> *MyId[0] = (unsigned char *)12;
> *MyId[1] = (unsigned char *)13;
>
> So on an so forth.

No, because you never allocated any memory for MyId to point to.

DS

[John Smith]

"David Schwartz" <davids@webmaster.com> wrote in message
news:bet7l1$h1j$1@nntp.webmaster.com...

>
> "John Smith" <John_Smith273@cox.net> wrote in message
> news:RxnQa.1010$Ze.642@fed1read03...
>

> > Thanks for your kind response.

>

> > 1) I am trying to copy the string octet into MyId. The framwork I am

> working

> > in has a function called DecStrCopy (STYPE *destString, STYPE

*srcString).

> > So somehow I have to cast octet to STYPE.

>
> Okay, that's impossible. You can't copy data into a pointer, there's

no

> room.

I am sorry I made an error pasting the prototype. It is:

DecStrCopy (STYPE * destString, char * srcString)