Pointer passing fails

[Cnewbit]

Hi
I'm sorry if this is a simple or rather unintelligent question, I am a complete newbie and trying to learn pointers in C. Please bear with me.

I am trying to write two functions, one calls the other and passes in an argument:

int RegisterImage( const char * streamID, IMGStream & c ) {
...
}

int OpenImage( const char * streamid, int dsize ) {
ImageStream * im;
int idx = -1;

if ( GetImgRegIdx(streamid, dsize, im) )
          idx = RegisterImage (streamid, im);
return idx;
}

The calling of "RegisterImage()" fails. It complains about:
"in passing argument 2 of ‘int Core::RegisterImage(const char*, IMGStream&)’"

Can anybody help me understand why it's complaining, and how to fix it?
Thanks so much

[grumpy]

A reference and a pointer are different things. You're trying to supply a pointer to a function expecting a reference.

im needs initialised so it points at a valid object - your code is not doing that. If you don't also fix that, the fix will get the compiler to accept the code but result in undefined behaviour.

All you need to do is dereference a pointer (prefix it with an asterix) to get a reference.

[Cnewbit]

A reference and a pointer are different things. You're trying to supply a pointer to a function expecting a reference.

I assume that, somewhere, im is initialised so it points at a valid object. If not, the fix will result in undefined behaviour.

All you need to do is dereference a pointer (prefix it with an asterix) to get a reference.

Great, that's what I thought at first and I tried this:
idx = RegisterImage (streamid, &im)

but it failed with pretty much the same error..i'm so confused! please help

Thanks

[grumpy]

An asterix is not an ampersand.

[oogabooga]

An asterix is not an ampersand.

Neither is a comic book character a punctuation character.

(Asterix == comic book character; asterisk == punctuation character.)

[grumpy]

Oh, the gall!

[Cnewbit]

Thanks guys, but does anybody have a solution to this? can anyone suggest how i can fix this?

Thanks

[tabstop]

Thanks guys, but does anybody have a solution to this? can anyone suggest how i can fix this?

Thanks

Asterisk = * ampersand = & they are not interchangeable so don't interchange them thanks

[c99tutorial]

If you're using references and compiling C++, it would be better to post this question in the C++ forum. References are not available in C.

[laserlight]

Indeed. Moved to C++ programming forum.

[hk_mp5kpdw]

Your RegisterImage function makes use of a IMGStream parameter, the value im that you are attempting to pass to it within the OpenImage function however is of type ImageStream. Is this a typo? Is one a typedef for the other or are they truly different things?