Memory Allocation in Managed C++ Results in Exception

  • Thread starter Thread starter Tyler
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T

Tyler

I have what I imagine is a very simple Managed C++ memory allocation
question. I have the following line of code in a static method of a managed
C++ class that always generate a System.NullReferenceException ("Object
reference not set to an instance of an object."):

char * ptvszHexString = new char[100];

Can someone tell me what I am missing?

Thanks, Tyler
 
Hi Tyler,

I test the following managed class in my MC++ program, it works fine:
__gc class testClass{
public:
static void testM1(){
char* ptvszHexString = new char[100];
}
};

Would you please paste some corresponding code snippet(self-contain) and
give some information about your sample program to let us isolate your
problem?


Thanks!

Best regards,

Gary Chang
Microsoft Online Partner Support

Get Secure! - www.microsoft.com/security
This posting is provided "AS IS" with no warranties, and confers no rights.
--------------------
 
Thanks Gary,

Knowing that it worked for you meant that I was definitely doing something
wrong. I think the problem is that I had not followed the directions (I
didn't know there were any) for setting the properties of a Managed C++ DLL
project. When I attempted to create a small test project, my 'new' would
always generate an unresolved external.

I found the following MSDN article, http://support.microsoft.com/?id=814472,
and followed its directions. When I used the /NOENTRY, msvcrt.lib, removed
nocheckclr.obj, and added the DLLMainCRTStartup@12 reference, my problems
went away. I think my exception was caused because I was attempting to use
'libc' instead of 'msvcrt'.

Can you confirm that I needed to follow the directions in this article in
order to properly setup my project correctly?

Thanks, Tyler


Gary Chang said:
Hi Tyler,

I test the following managed class in my MC++ program, it works fine:
__gc class testClass{
public:
static void testM1(){
char* ptvszHexString = new char[100];
}
};

Would you please paste some corresponding code snippet(self-contain) and
give some information about your sample program to let us isolate your
problem?


Thanks!

Best regards,

Gary Chang
Microsoft Online Partner Support

Get Secure! - www.microsoft.com/security
This posting is provided "AS IS" with no warranties, and confers no rights.
--------------------
From: "Tyler" <[email protected]>
Subject: Memory Allocation in Managed C++ Results in Exception
Date: Mon, 31 May 2004 09:51:21 -0400
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I have what I imagine is a very simple Managed C++ memory allocation
question. I have the following line of code in a static method of a managed
C++ class that always generate a System.NullReferenceException ("Object
reference not set to an instance of an object."):

char * ptvszHexString = new char[100];

Can someone tell me what I am missing?

Thanks, Tyler
Click to expand...
Click to expand...
 
Hi Tyler,

I tested your sample code with a MC++ console project, it is really
different with your scenario.

Since the "new" operation of "char* ptvszHexString = new char[100];" is a C
run-time function(in vc7\crt\src\newaop.cpp), the program should load the C
run-time library first, you got the right directions from that KB.


Thanks!

Best regards,

Gary Chang
Microsoft Online Partner Support

Get Secure! - www.microsoft.com/security
This posting is provided "AS IS" with no warranties, and confers no rights.
--------------------
 
Thank you for that confirmation Gary. My application works fine now that I
have followed the directions in the article.

Thanks, Tyler
 
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