Converting a unsigned char * to const char *

[hamishd]

Is this possible? Sorry if this question isn't relevant here.

actually, I'm really trying to convert a unsigned char * to an int

[Jim Langston]

Re: Converting a unsigned char * to const char *

"hamishd" <Hamish.Dean@gm ail.comwrote in message
news:1186219573 .640775.272620@ x35g2000prf.goo glegroups.com.. .

Is this possible? Sorry if this question isn't relevant here.
>
actually, I'm really trying to convert a unsigned char * to an int

Are you trying to convert the value of the pointer, or where the pointer is
pointing to?

Either way, reinterpret_cas t is what you want.
reinterpret_cas t<int>( Foo );

[=?ISO-8859-1?Q?Erik_Wikstr=F6m?=]

Re: Converting a unsigned char * to const char *

On 2007-08-04 11:47, Jim Langston wrote:

"hamishd" <Hamish.Dean@gm ail.comwrote in message
news:1186219573 .640775.272620@ x35g2000prf.goo glegroups.com.. .

>Is this possible? Sorry if this question isn't relevant here.
>>
>actually, I'm really trying to convert a unsigned char * to an int

>
Are you trying to convert the value of the pointer, or where the pointer is
pointing to?
>
Either way, reinterpret_cas t is what you want.
reinterpret_cas t<int>( Foo );

reinterpret_cas t should not be needed it it's a unsigned char -int
conversion the OP is trying to do, both are integer types so a normal
assignment should do, right?

--
Erik Wikström

[Barry]

Re: Converting a unsigned char * to const char *

Jim Langston wrote:

"hamishd" <Hamish.Dean@gm ail.comwrote in message
news:1186219573 .640775.272620@ x35g2000prf.goo glegroups.com.. .

>Is this possible? Sorry if this question isn't relevant here.
>>
>actually, I'm really trying to convert a unsigned char * to an int

>
Are you trying to convert the value of the pointer, or where the pointer is
pointing to?
>
Either way, reinterpret_cas t is what you want.
reinterpret_cas t<int>( Foo );
>
>

I think reinpterpret_ca st does *NOT* work with constness
maybe static_cast and const_cast together will work

[Barry]

Re: Converting a unsigned char * to const char *

Erik Wikström wrote:

reinterpret_cas t should not be needed it it's a unsigned char -int
conversion the OP is trying to do, both are integer types so a normal
assignment should do, right?
>

you can assign unsigned char* to int

I think reinterpret_cas t is fine here

[Ian Collins]

Re: Converting a unsigned char * to const char *

hamishd wrote:

Is this possible? Sorry if this question isn't relevant here.
>
actually, I'm really trying to convert a unsigned char * to an int
>

There isn't a portable way to do this, on many systems a char* is bigger
than an int.

--
Ian Collins.

[hamishd]

Re: Converting a unsigned char * to const char *

On Aug 4, 6:47 pm, "Jim Langston" <tazmas...@rock etmail.comwrote :

"hamishd" <Hamish.D...@gm ail.comwrote in message
>
news:1186219573 .640775.272620@ x35g2000prf.goo glegroups.com.. .
>

Is this possible? Sorry if this question isn't relevant here.

>

actually, I'm really trying to convert a unsigned char * to an int

>
Are you trying to convert the value of the pointer, or where the pointer is
pointing to?
>
Either way, reinterpret_cas t is what you want.
reinterpret_cas t<int>( Foo );

Below is exactly what I'm doing. I want to read a value from the
registry. Let's say the registry value is "453".

unsigned char ikey[256];
ULONG ilen = 256;
HKEY ihKey;

RegQueryValueEx (ihKey, "Value", 0, NULL, ikey, &ilen);

But now ikey is not an int, i want an int of value 453.

int RegistryVal = reinterpret_cas t<int>(ikey);

This does not work.
The reason i asked about converting to a constr char * is that I
wanted to use atoi()

[Ian Collins]

Re: Converting a unsigned char * to const char *

hamishd wrote:

On Aug 4, 6:47 pm, "Jim Langston" <tazmas...@rock etmail.comwrote :

>"hamishd" <Hamish.D...@gm ail.comwrote in message
>>
>news:118621957 3.640775.272620 @x35g2000prf.go oglegroups.com. ..
>>

>>Is this possible? Sorry if this question isn't relevant here.
>>actually, I'm really trying to convert a unsigned char * to an int

>Are you trying to convert the value of the pointer, or where the pointer is
>pointing to?
>>
>Either way, reinterpret_cas t is what you want.
>reinterpret_ca st<int>( Foo );

>
Below is exactly what I'm doing. I want to read a value from the
registry. Let's say the registry value is "453".
>
unsigned char ikey[256];
ULONG ilen = 256;
HKEY ihKey;
>
RegQueryValueEx (ihKey, "Value", 0, NULL, ikey, &ilen);
>
But now ikey is not an int, i want an int of value 453.
>

What does RegQueryValueEx do to the ikey parameter?

int RegistryVal = reinterpret_cas t<int>(ikey);
>
This does not work.

Why should it?

The reason i asked about converting to a constr char * is that I
wanted to use atoi()
>

Why not just use static_cast<cha r*>(ikey)?

--
Ian Collins.

[BobR]

Re: Converting a unsigned char * to const char *


Ian Collins <ian-news@hotmail.co mwrote in message...

hamishd wrote:

Is this possible? Sorry if this question isn't relevant here.
actually, I'm really trying to convert a unsigned char * to an int

There isn't a portable way to do this, on many systems a char* is bigger
than an int.
>

unsigned char *uc( 0 );
int int16bit( reinterpret_cas t<int>(uc) & 0xFF );

But it wouldn't be logical. <G>

--
Bob R
POVrookie

[Jim Langston]

Re: Converting a unsigned char * to const char *

"hamishd" <Hamish.Dean@gm ail.comwrote in message
news:1186272165 .221239.20150@e 9g2000prf.googl egroups.com...

On Aug 4, 6:47 pm, "Jim Langston" <tazmas...@rock etmail.comwrote :

>"hamishd" <Hamish.D...@gm ail.comwrote in message
>>
>news:118621957 3.640775.272620 @x35g2000prf.go oglegroups.com. ..
>>

Is this possible? Sorry if this question isn't relevant here.

>>

actually, I'm really trying to convert a unsigned char * to an int

>>
>Are you trying to convert the value of the pointer, or where the pointer
>is
>pointing to?
>>
>Either way, reinterpret_cas t is what you want.
>reinterpret_ca st<int>( Foo );

>
Below is exactly what I'm doing. I want to read a value from the
registry. Let's say the registry value is "453".
>
unsigned char ikey[256];
ULONG ilen = 256;
HKEY ihKey;
>
RegQueryValueEx (ihKey, "Value", 0, NULL, ikey, &ilen);
>
But now ikey is not an int, i want an int of value 453.
>
int RegistryVal = reinterpret_cas t<int>(ikey);
>
This does not work.
The reason i asked about converting to a constr char * is that I
wanted to use atoi()

Oh. You want to convert "453" to an int. I would use stringstream, which
is an alternative to atoi

std::stringstre am convert;
convert << ikey;
int Value;
convert >value;

std::string convert( ikey );
int Value;
convert >Value;

may also work. Not sure if stringstream has a constructor taking a char*

[BobR]

Re: Converting a unsigned char * to const char *


hamishd <Hamish.Dean@gm ail.comwrote in message...

On Aug 4, 6:47 pm, "Jim Langston" <tazmas...@rock etmail.comwrote :

"hamishd" <Hamish.D...@gm ail.comwrote in message

Is this possible? Sorry if this question isn't relevant here.
actually, I'm really trying to convert a unsigned char * to an int

Are you trying to convert the value of the pointer, or where the pointer

is

pointing to?
Either way, reinterpret_cas t is what you want.
reinterpret_cas t<int>( Foo );

>
Below is exactly what I'm doing. I want to read a value from the
registry. Let's say the registry value is "453".
>
unsigned char ikey[256];
ULONG ilen = 256;
HKEY ihKey;
RegQueryValueEx (ihKey, "Value", 0, NULL, ikey, &ilen);
>
But now ikey is not an int, i want an int of value 453.
>
int RegistryVal = reinterpret_cas t<int>(ikey);
This does not work.

The reason i asked about converting to a constr char * is that I
wanted to use atoi()

Why?

#include <iostream>
#include <sstream>

{ // main() or ?
unsigned char ikey[256] = "453\0";
std::stringstre am sis;
sis << ikey;
int number;
sis >number;
std::cout<<"num ber = "<<number<<std: :endl;
}
// out: number = 453

--
Bob R
POVrookie

[BobR]

Re: Converting a unsigned char * to const char *


Jim Langston <tazmaster@rock etmail.comwrote in message...

"hamishd" <Hamish.Dean@gm ail.comwrote in message...

Below is exactly what I'm doing. I want to read a value from the
registry. Let's say the registry value is "453".

unsigned char ikey[256];
ULONG ilen = 256;
HKEY ihKey;
RegQueryValueEx (ihKey, "Value", 0, NULL, ikey, &ilen);
But now ikey is not an int, i want an int of value 453.
int RegistryVal = reinterpret_cas t<int>(ikey);
This does not work.
The reason i asked about converting to a constr char * is that I
wanted to use atoi()

>
Oh. You want to convert "453" to an int. I would use stringstream, which
is an alternative to atoi
>
std::stringstre am convert;
convert << ikey;
int Value;
convert >value;
>

// std::string convert( ikey );

std::string Sconvert( ikey );
std::stringstre am convert( Sconvert );

Nope, I tried it. (and the casts got real ugly! <G>).

int Value;
convert >Value;
>
may also work. Not sure if stringstream has a constructor taking a char*

It does for 'char*', but not for 'unsigned char*' (not on my old MinGW).

// -------
char const scc[] = "453\0";
std::istringstr eam is( scc ); // no problem
// -------
unsigned char const scc[] = "453\0";
std::istringstr eam is( scc );
// error: invalid conversion from `const unsigned char*' to `
// const char*'
// error: initializing argument 1 of std::basic_stri ng...
(again, the casts got real ugly! <G>).
// -------

--
Bob R
POVrookie