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Rick Venter
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 Posted: Fri Apr 23, 2004 4:10 pm Post subject: compile warnings in VC 6.0 using list<string> |
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I am trying to use list<string> and it gives me a compile time error
in VC 6.0
The following is the code snippet,
//this is in a .h file
class foo
{
public:
// Ensures only a single instance of this class is instantiated -
static foo* Instance();
// Dtor
virtual ~foo();
protected:
// Ctor. Clients cannot call this
foo() {};
private:
// only one of this is ever created
static foo *m_pCLMObj;
list<string> lst;
};
And the follwing is thw warning that I get
c:program filesmicrosoft visual studiovc98includelist(125) :
warning C4786: '?$reverse_bidirectional_iterator@Viterator@?$list@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V?$allocator@V?$basic_string@DU?$char_traits@D@std@@V?$
allocator@D@2@@std@@@2@@std@@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@3@AAV43@PAV43@H'
: identifier was truncated to '255' characters in the browser
information
e:foo.h(15) : see reference to class template instantiation
'std::list<class std::basic_string
std::char_traits,class
std::allocator<class std::b
asic_string
std::allocator<char> > > >' being compiled
c:program filesmicrosoft visual studiovc98includelist(128) :
warning C4786: '?$reverse_bidirectional_iterator@Vconst_iterator@?$list@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V?$allocator@V?$basic_string@DU?$char_traits@D@st
d@@V?$allocator@D@2@@std@@@2@@std@@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@3@ABV43@PBV43@H'
: identifier was truncated to '255' characters in the browser
information
e:foo.h(15) : see reference to class template instantiation
'std::list<class std::basic_string
std::char_traits,class
std::allocator<class std::b
asic_string
std::allocator<char> > > >' being compiled
I cant seem to figure out what the matter is, can anyone help?
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Antoun Kanawati
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| Posted: Sat Apr 24, 2004 12:38 am Post subject: Re: compile warnings in VC 6.0 using list<string> |
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The following are warnings, not errors, telling you about the
limitations of debug-mode. Basically, template instantiations
are creating mangles symbols that do not fit in some debugging
symbol table. If you compile in release-mode you will not see
these warnings.
You can switch them off with a pragma.
#pragma warning(disable: 4786)
After some trial and error, you'll get all your pragmas in the right
places, and the noise would go down to a decent level.
Rick Venter wrote:
| Quote: | I am trying to use list<string> and it gives me a compile time error
in VC 6.0
The following is the code snippet,
//this is in a .h file
class foo
{
public:
// Ensures only a single instance of this class is instantiated -
static foo* Instance();
// Dtor
virtual ~foo();
protected:
// Ctor. Clients cannot call this
foo() {};
private:
// only one of this is ever created
static foo *m_pCLMObj;
list<string> lst;
};
And the follwing is thw warning that I get
c:program filesmicrosoft visual studiovc98includelist(125) :
warning C4786: '?$reverse_bidirectional_iterator@Viterator@?$list@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V?$allocator@V?$basic_string@DU?$char_traits@D@std@@V?$
allocator@D@2@@std@@@2@@std@@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@3@AAV43@PAV43@H'
: identifier was truncated to '255' characters in the browser
information
e:foo.h(15) : see reference to class template instantiation
'std::list<class std::basic_string
std::char_traits,class
std::allocator<class std::b
asic_string
std::allocator<char> > > >' being compiled
c:program filesmicrosoft visual studiovc98includelist(128) :
warning C4786: '?$reverse_bidirectional_iterator@Vconst_iterator@?$list@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V?$allocator@V?$basic_string@DU?$char_traits@D@st
d@@V?$allocator@D@2@@std@@@2@@std@@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@3@ABV43@PBV43@H'
: identifier was truncated to '255' characters in the browser
information
e:foo.h(15) : see reference to class template instantiation
'std::list<class std::basic_string
std::char_traits,class
std::allocator<class std::b
asic_string
std::allocator<char> > > >' being compiled
I cant seem to figure out what the matter is, can anyone help?
|
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moswald
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| Posted: Sat Apr 24, 2004 12:39 am Post subject: Re: compile warnings in VC 6.0 using list<string> |
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In VC6, debug objects can't have identifiers longer than 255 characters.
In your case, you've got an item that, due to the template name mangling,
is very long. VC6 is just warning you that when you debug your program,
you won't be able to access any debug information about this object.
In VC7 this is not a problem (at least, it never has been in my
experience).
Your best bet is to just #pragma warning(disable:4786) the header.
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Ben Hutchings
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| Posted: Sat Apr 24, 2004 12:41 am Post subject: Re: compile warnings in VC 6.0 using list<string> |
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Rick Venter wrote:
| Quote: | I am trying to use list<string> and it gives me a compile time error
in VC 6.0
snip
And the follwing is thw warning that I get
c:program filesmicrosoft visual studiovc98includelist(125) :
warning C4786: '?$reverse_bidirectional_iterator@Viterator@?$list@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V?$allocator@V?$basic_string@DU?$char_traits@D@std@@V?$
allocator@D@2@@std@@@2@@std@@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@3@AAV43@PAV43@H'
: identifier was truncated to '255' characters in the browser
information
snip
I cant seem to figure out what the matter is, can anyone help?
|
Your code is fine, but you have run into a compiler limitation. So
far as I know, you can safely disable this warning (using
#pragma warning).
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
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Eugene Gershnik
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| Posted: Wed Apr 28, 2004 7:44 pm Post subject: Re: compile warnings in VC 6.0 using list<string> |
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moswald wrote:
| Quote: | In VC6, debug objects can't have identifiers longer than 255
characters. In your case, you've got an item that, due to the
template name mangling, is very long. VC6 is just warning you that
when you debug your program, you won't be able to access any debug
information about this object.
|
This is not entirely correct. The warning tells exactly what happened - name
was truncated to 255 characters. You _will_ be able to debug and access
debug information. However, if you happen to have more than one symbol with
mangled names that differ only after 255 characters, the debugger may have
trouble displaying them. In practice I have never seen this to be a problem.
Template instantiations that usually result in this warning start to differ
well before 255 limit. Maybe it is possible to construct an artificial
example that will have a real problem but for all practical purposes the
warning can be safely ignored.
| Quote: | Your best bet is to just #pragma warning(disable:4786) the header.
|
Agreed.
--
Eugene
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
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