Maps, Iterators and Templated Classes

[jschon]

Hi,
I'm trying to write a thread safe hash map class. Basically I have put
some packaging around the STL map class to ensure thread safe access.
The container is a templated class.

I'm having trouble with a line of code:

map<string, T*>::iterator all_it = all.begin();

when i compile it i get the error:
objectcontainer.cpp:127: error: expected `;' before "all_it"

however if i change the line of code to:
map<string, int*>::iterator all_it = all.begin();

the error completely goes away.

the function this code snippet is in is defined as such:
template <class T>
void ObjectContainer<T>::copy(const ObjectContainer<T>& o){
---body---
}
if anybody knows what I am doing incorrectly I would be very much
obliged if you could let me know, or give me some tips. I'm VERY stuck
here.

Thanks!,
Jake

[Victor Bazarov]

js****@umich.edu wrote:

I'm trying to write a thread safe hash map class. Basically I have
put some packaging around the STL map class to ensure thread safe
access. The container is a templated class.

I'm having trouble with a line of code:

map<string, T*>::iterator all_it = all.begin();

when i compile it i get the error:
objectcontainer.cpp:127: error: expected `;' before "all_it"

however if i change the line of code to:
map<string, int*>::iterator all_it = all.begin();

the error completely goes away.

the function this code snippet is in is defined as such:
template <class T>
void ObjectContainer<T>::copy(const ObjectContainer<T>& o){
---body---
}
if anybody knows what I am doing incorrectly I would be very much
obliged if you could let me know, or give me some tips. I'm VERY
stuck here.

This is covered in the FAQ. See section 35, at the end. Or search for
"dependent name". What you need is to tell the compiler that what you
are using is a type by prepending your declaration with 'typename'.

V
--
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[Thorsten Kiefer]

js****@umich.edu wrote:

I'm having trouble with a line of code:

map<string, T*>::iterator all_it = all.begin();

typename map<string, T*>::iterator all_it = all.begin();

[jschon]

Perfect. I didn't see the FAQ, i'm new to Bulletin Board questions.
I'll look into that next time.

Thanks for the help, that worked perfectly. I have never heard of that
rule before

Thanks again!
-jake-

[Thorsten Kiefer]

I had the same problem once, and it took me about an hour find the
solution ;)
js****@umich.edu wrote:

Perfect. I didn't see the FAQ, i'm new to Bulletin Board questions.
I'll look into that next time.

Thanks for the help, that worked perfectly. I have never heard of that
rule before

Thanks again!
-jake-