When I create a new C++ project of type "Class Library (.NET)", I am
unable to then add the following line of code :
using namespace std
If I do, I get the following error on compilation :
c:\Research\Cod e\Visual Studio\TestC++2 \TestC++2.h(7): error
C2871: 'std' : a namespace with this name does not exist
If I try this with other project types, e.g. "Console Application
(.NET)" projects, I have no such problem.
Any ideas on what I can do to fix this (as I would like to use
functions from <string.h> in my code).
Thanks,
Alex. 6 4526
AlexD_UK wrote: When I create a new C++ project of type "Class Library (.NET)", I am unable to then add the following line of code : using namespace std
If I do, I get the following error on compilation : c:\Research\Cod e\Visual Studio\TestC++2 \TestC++2.h(7): error C2871: 'std' : a namespace with this name does not exist
If I try this with other project types, e.g. "Console Application (.NET)" projects, I have no such problem.
Any ideas on what I can do to fix this (as I would like to use functions from <string.h> in my code).
Use #include<string > rather than <string.h> Thanks,
Alex.
--
Jacobo Rodríguez Villar
TyphoonLabs Lead Programmer http://www.typhoonlabs.com
"Jacobo Rodriguez Villar" <skdjf@sdkjf> wrote in message
news:%2******** ********@tk2msf tngp13.phx.gbl. .. AlexD_UK wrote: When I create a new C++ project of type "Class Library (.NET)", I am unable to then add the following line of code : using namespace std
If I do, I get the following error on compilation : c:\Research\Cod e\Visual Studio\TestC++2 \TestC++2.h(7): error C2871: 'std' : a namespace with this name does not exist
If I try this with other project types, e.g. "Console Application (.NET)" projects, I have no such problem.
Any ideas on what I can do to fix this (as I would like to use functions from <string.h> in my code).
Use #include<string > rather than <string.h>
Thanks,
Alex.
-- Jacobo Rodríguez Villar
TyphoonLabs Lead Programmer
http://www.typhoonlabs.com
Actually, #include <string> will get you the C++ string class, not what is
in <string.h>.
What you want is
#include <cstring>
which is the c++ equivalent of string.h
Thanks to you both.
When I try the first option with new Class Library (.NET) project and
the following code :
// TestC5.h
#pragma once
#include <string>
using namespace System;
namespace TestC5
{
public __gc class Class1
{
};
void method(void)
{
char str1[]= "To be or not to be";
char str2[6];
strncpy (str2,str1,5);
}
}
I get this error :
TestC++5 error LNK2020: unresolved token (0A000006) _CxxThrowExcept ion
TestC++5 error LNK2020: unresolved token (0A000017) delete
If I substitute for #include <cstring>, I get :
TestC++5 error LNK2001: unresolved external symbol "char * __cdecl
strncpy(char *,char const *,unsigned int)"
(?strncpy@@$$J0 YAPADPADPBDI@Z)
Am I missing another import library?
Alex.
Nope, strncpy is in the runtime, not import libraries
--
cheers,
Costea Bogdan
"AlexD_UK" wrote: Thanks to you both.
When I try the first option with new Class Library (.NET) project and the following code :
// TestC5.h #pragma once #include <string> using namespace System;
namespace TestC5 { public __gc class Class1 { };
void method(void) { char str1[]= "To be or not to be"; char str2[6]; strncpy (str2,str1,5); } }
I get this error : TestC++5 error LNK2020: unresolved token (0A000006) _CxxThrowExcept ion TestC++5 error LNK2020: unresolved token (0A000017) delete
If I substitute for #include <cstring>, I get : TestC++5 error LNK2001: unresolved external symbol "char * __cdecl strncpy(char *,char const *,unsigned int)" (?strncpy@@$$J0 YAPADPADPBDI@Z)
Am I missing another import library?
Alex.
Costea,
Thanks - so can you think of any reason why my project is not
compiling?
Do I need to use a different version of the runtime to the one that I
am given by default when creating a VS C++ Class Library (.NET)
project?
Alex.
"Costea Bogdan bcostea.ro>" <bogdan<at> wrote in message news:<42******* *************** ************@mi crosoft.com>... Nope, strncpy is in the runtime, not import libraries -- cheers, Costea Bogdan
"AlexD_UK" <al*********@ho tmail.com> wrote in message
news:e3******** *************** ***@posting.goo gle.com... When I try the first option with new Class Library (.NET) project and the following code :
// TestC5.h #pragma once #include <string> using namespace System;
namespace TestC5 { public __gc class Class1 { };
void method(void) { char str1[]= "To be or not to be"; char str2[6]; strncpy (str2,str1,5); } }
I get this error : TestC++5 error LNK2020: unresolved token (0A000006) _CxxThrowExcept ion TestC++5 error LNK2020: unresolved token (0A000017) delete
strncpy is part of the <cstring> header of the std namespace, not System
namespace which is part of the .net <mscorlib.dll >. Also, you need to make
sure you allocate enough n characters in strncpy(str2, str1, n) or it will
truncate. n needs to allocate enough room for the string plus the null
character at the end.
Just using standard c++, here's how I would rewrite and compile the code:
#include <cstring>
#include <iostream>
using namespace std;
int main()
{
const char str1[] = "To be or not to be";
char str2[24];
strncpy(str2,st r1,23);
cout << str1 << endl;
cout << str2 << endl;
}
I do though, get this warning when compiling with VS.NET 8.0 beta:
cstrcpy.cpp(9) : warning C4996: 'strncpy' was declared deprecated
D:\Program Files\Microsoft Visual Studio 8\VC\include\st ring.h(121)
: see declaration of 'strncpy'
Microsoft (R) Incremental Linker Version 8.00.40607.16
Copyright (C) Microsoft Corporation. All rights reserved.
It is unsafe and cumbersome to use C style chars. Better to use safer
standard C++ strings:
#include <iostream>
#include <string>
using namespace std;
int main()
{
string str1 = "To be or not to be";
string str2 = str1;
cout << str1 << endl;
cout << str2 << endl;
}
str1 can be as long or short as you want, and you don't have to worry about
allocating enough when copying it to str2.
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