CRegKey

Hi, I'm wondering about something here. How would you detect if a user has a key value in the registry, and if it's not there, create one? The code (at end of post) a friend of mine and me are using doesn't do this. What it does is crash if the m_hKey is NULL.

Code:

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                m_regApp.Create(HKEY_CURRENT_USER, "Software\\TriFaze\\Jam MP3\\");

                if(m_regApp.m_hKey == NULL){
                        TRACE("Unable to set m_hKey!\n");
                } else{
                        TRACE("m_hKey set!\n");
                }

                // Write the new registry settings
            m_regApp.Open(HKEY_CURRENT_USER, "Software\\TriFaze\\Jam MP3\\");  // Get last saved directory
                m_regApp.SetValue(myMusic, "LastDir");    // Set new directory
                m_regApp.SetValue("255", "LastVolume");    // Set new volume level
               
                if(!m_regApp.QueryValue(drive, "SelectDrive", (DWORD*)&m_dwRead)){
                        if(ccd.DoModal() == ID_OK){
                                m_regApp.QueryValue(drive, "SelectDrive", (DWORD*)&m_dwRead);
                        }
                }

                m_regApp.Close();    // Close the key

---

(PS: Thanks in advance for any help)

try

"Software\\TriFaze\\Jam MP3"

and

Is the handle NULL before the call to Create() ? If not why not?

then

test the return from the Create() == ERROR_SUCCESS and if not call GetLastError() to find out why.

Quote:

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Originally Posted by novacain

try

"Software\\TriFaze\\Jam MP3"

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Either way works just the same.

Quote:

---

Originally Posted by novacain

and

Is the handle NULL before the call to Create() ? If not why not?

---

It seems to be before the call.

Quote:

---

Originally Posted by novacain

then

test the return from the Create() == ERROR_SUCCESS and if not call GetLastError() to find out why.

---

It does return ERROR_SUCCESS.

** EDIT: Added results **

Try an Open(). If that fails then use a Create().

It may be the reg key exists and so the m_hkey is not attatched automatically by the Create() (but the Create() still returns a success because the reg key is there)

Quote:

---

Originally Posted by novacain

Try an Open(). If that fails then use a Create().

It may be the reg key exists and so the m_hkey is not attatched automatically by the Create() (but the Create() still returns a success because the reg key is there)

---

I forgot to add that in to the code I posted above, but it was there.

Anyways though, I decided to do store them in a file, but a new problem arises. When I try to save the directory that was last used, it fails to right the directory (If the directory is C:\Program Files\Pie Is Good\, it'd only save C:\P). Below is the code for it:

Code:

---

#pragma once

#include <stdio.h>
#include <stdlib.h>

static FILE *fp;

static DWORD dwBytes;

static CString fn;

static BOOL bRW = FALSE;
static BOOL SaveSetting(char *filename, char *text);
static BOOL ReadSetting(char *filename, char *store);

BOOL SaveSetting(char *filename, char *text){
        fn.Empty();
        fn.Format("%s.jp3", filename);

        fp = fopen(fn, "wt");

        if(fp != NULL){
                if(fwrite(text, sizeof(char*), strlen(text), fp) != 1){
                        TRACE("fwrite() did not write the file properly!\n");
                        AfxMessageBox("fwrite() failed!");

                        return FALSE;
                } else{
                        TRACE("fwrite() did write the file properly!\n");
                       
                        return TRUE;
                }

                return TRUE;
        } else{
                TRACE("fp is empty.  No file was opened nor created.\n");
                AfxMessageBox("fp is empty.  No file was opened nor created.");

                return FALSE;
        }

        return TRUE;
}

---

You should probably modify filename (or fn) to replace '\', which are escape characters, with "\\". For example C:\Program Files\Pie Is Good\ becomes C:\\Program Files\\Pie Is Good\\

Quote:

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Originally Posted by Ken Fitlike

You should probably modify filename (or fn) to replace '\', which are escape characters, with "\\". For example C:\Program Files\Pie Is Good\ becomes C:\\Program Files\\Pie Is Good\\

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Well, the way the code works is that the file is created in the same directory as the exe. So, I don't think that's the problem, because the other files are written perfectly.

Try sizeof(char) instead of sizeof(char*) in your fwrite call:

Code:

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fwrite(text, sizeof(char), strlen(text), fp)

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Quote:

---

Originally Posted by Ken Fitlike

Try sizeof(char) instead of sizeof(char*) in your fwrite call:

Code:

---

fwrite(text, sizeof(char), strlen(text), fp)

---

---

Thank you :)

Why would that make a difference though (it worked though)?

One other thing, now my reading code is causing trouble:

Code:

---

BOOL ReadSetting(char *filename, char *store){
        fn.Empty();
        fn.Format("%s.jp3", filename);

        fp = fopen(fn, "rt");

        if(fp != NULL){
                if(fread(store, sizeof(char), strlen(store), fp) != 1){
                        TRACE("fread() did not read the file properly!\n");
                        AfxMessageBox("fread() failed!");

                        return FALSE;
                } else{
                        TRACE("fread() did read the file properly!\n");
                       
                        return TRUE;
                }

                return TRUE;
        } else{
                TRACE("fp is empty.  No file was opened nor read.\n");
                AfxMessageBox("fp is empty.  No file was opened nor read.");
       
                return FALSE;
        }

        return TRUE;
}

---

The problem is that I get the "fread() failed!" whenever I try to read the file. Maybe it has to deal w/ the "!= 1" if statement?

>>Why would that make a difference though (it worked though)?

sizeof(char) != sizeof(char*)


>>if(fread(store, sizeof(char), strlen(store), fp) != 1){


strlen(store) == the number of characters already in store

so if store empty == 0

you want the size of the char array - 1