Why we are using :: before a function

Question

0.00/5 (No votes)

See more:

Hi all,

I have seen a VC++ code.

::FindNextFile().It is an MFC function.Can we call this function without using "::"

operator.If then why we are using :: operator.Also i have seen same calling

procedure in an user defined function.And it is

C++

::DisplayMessage(&m_RichEditLog,csMessage,1);

And the corresponding .CPP file is

C++

------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
DWORD CALLBACK RichEditStreamInCallBack(DWORD dwCookie,LPBYTE pbBuff,LONG cb, LONG *pcb)
{
	return 0;
}
void DisplayMessage(CRichEditCtrl * pRichEdit,const CString &cstrMessage,int nFlags/*=FALSE*/)
{

	
	
}

void SaveText(CRichEditCtrl * pRichEdit,const CString & strFile)
{
	
}

DWORD CALLBACK RichEditStreamOutCallBack(DWORD dwCookie, LPBYTE pbBuff, LONG cb, LONG *pcb)
{

	return 0;
}

------------------------------------------------------------------------------------------------------------------------------------------------------------------------

.h file is

C++

------------------------------------------------------------------------------------------------------------------------------------------------------------------------

DWORD CALLBACK RichEditStreamInCallBack(DWORD dwCookie,LPBYTE pbBuff,LONG cb, LONG *pcb);

void DisplayMessage(CRichEditCtrl * pRichEdit,const CString & cstrMessage,int nFlags/*=FALSE*/);

void SaveText(CRichEditCtrl * pRichEdit,const CString & strFile);
static DWORD CALLBACK RichEditStreamOutCallBack(DWORD dwCookie, LPBYTE pbBuff, LONG cb, LONG *pcb);

------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Please help me.

Thanks in advance

Posted 14-Dec-11 18:41pm

kutz 2

Updated 14-Dec-11 18:50pm

Wendelius

v2

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Resmi Anna · Answer 1 · 2011-12-14T19:05:00

This is used in situations where you have function in your class with its name same as one in win32 API(global function) function name. for example, within the Visual studio file "AFXWIN.h", we have a function called AfxMessageBox(). suppose you have a class CMyClass. It also has a function called AfxMessageBox(). your class header includes the file "AFXWIN.h".

C++

#include <afxwin.h>
....
....
class MyClass
{
....
int AfxMessageBox(...)
{
 //DO SOMETHING
}
....
}
.........</afxwin.h>

When you call the function AfxMessageBox() from your class, it will point to the member function AfxMessageBox() in your class. But what if you want to call the MFC function AfxMessageBox()??.
That time you call it like

C++

::AfxMessageBox()