Monday, September 22, 2008

Skype: Belkin Skype Phone

One of the nice things about skype is that you can download it for Mac, Linux or Windows, so you aren't particularly tied down.

Skype is a DIY voip service. They offer a skype out unlimited subscription for canada and the usa (unlimited outgoing calling from your computer to landlines and cellphones) for $30. If you choose you can also get a phone number in whatever USA area code you want for another $30. I am sad that there still are no numbers available in canada. Because skype online numbers are available in over 20 countries at the time of this writing, i wouldn't be surprised if canada has extra red tape, which is preventing this.

So for the cost of $5 computer speakers, $5 computer microphone, an internet connection and $60/year ($5/month) you can scrap your $30/month landline. Don't forget to read the fine print, skype wants you to know that you can't use it for 911 calling, because the 911 operators have no idea where you are calling from. You could be online in europe and still take skype calls at your 801 usa area code through your internet connection. So... it is important to keep an old cell phone around. Even deactivated/non-sim card cell phones are required by law to be able to call 911.

My wife doesn't like using the computer for calling much, plus we don't want to leave it on 24/7 to take calls so we were thinking of getting the belkin skype desktop phone. This phone is a no computer required phone. It seems a little pricey considering it is just a phone... but understood what the skype phone really is, its pretty much an $80 computer with built-in microphone and speakers.

There are a lot of items for sale which replace your microphone and speakers... some usb phones, some cordless phones (comp req'd), other cordless phones (comp not req'd), and even wifi phones. Wifi is great... if you get a wifi hotspot anywhere you can make or take calls. I have heard the battery life on them isn't great yet... because it just like a minilaptop- but you can't turn the wifi network card off for power saving mode!

Thursday, September 11, 2008

C++ : How to Launch a Background in Windows Program

In linux it is easy to launch a background process at the command line with ampersand.

./app_to_launch &

In windows there is no easy command line suffix which will launch your program in the background. However it is relatively easy to code one up. If you install Visual C++ Express 2005, and the Microsoft Platform SDK (see configuration below) just compile this application as BKLAUNCH.exe and you will soon be able launch apps in the background from batch files.

I created an empty win32 project named BKLAUNCH, no precompiled header, and compiled the following code.
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#include <windows.h>
#include <shellapi.h>
#include <tchar.h>

int _tmain(int argc, _TCHAR* argv[])
if (argc!=2)
printf(" BKLAUNCH.EXE [apptolaunch]\n");
printf(" BKLAUNCH.EXE notepad.exe\n");
ShellExecute(NULL, TEXT("open"), argv[1], NULL, NULL, SW_SHOW);
return 0;

Once BKLAUNCH has successfully compiled, place it in a folder that is in the PATH. Now, go to Start > Run > cmd.exe [OK], and enter the following:
BKLAUNCH notepad.exe

You will notice notepad.exe is launched in the background, perfect for batch files.

If you are like me and use default settings, look under
Project > Project Properties > Linker > Input > Additional Dependencies
it will will have only kernel32.lib. When you compile there will be linker errors.

Because of the #include <windows.h> and #include <shellapi.h>
you need to add the following to your Additional Dependencies
kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib in order to resolve the linker errors.

Microsoft Platform SDK Config
In order to use the MS Platform SDK in Visual C++ Express 2005, you have make the platform SDK visible to the compiler.

Go to
Tools > Options > Projects and Solutions > VC++ Directories > Platform=Win32 > Show Directories for=include files
Add to the list,
C:\Program Files\Microsoft Platform SDK for Windows Server 2003 R2\Include
(or wherever you installed the MS Platform SDK\Include)

Now, go to
Tools > Options > Projects and Solutions > VC++ Directories > Platform=Win32 > Show Directories for=library files
Add to the list,
C:\Program Files\Microsoft Platform SDK for Windows Server 2003 R2\Lib
(or wherever you installed the MS Platform SDK\Lib)

Tuesday, September 09, 2008

BASH: bad interpreter: No such file or directory

-bash: ./ /usr/bash^M: bad interpreter: No such file or directory

Dos text files use \r\n (0xD 0xA) as their end of line characters. Unix text files use \n (0xA) as their end of line character. What happened here is I had a file in dos text format, and tried to execute it in bash. the ^M you see above is saying "It wasn't expecting the \r character".


use dos2unix
[user@linux1 ~] dos2unix
dos2unix: converting files to UNIX format...

Monday, September 08, 2008

C++: Simple Makefile Example

I have always been looking for a nice makefile template, that will allow me to have separate include, src, and obj directories. Today I stumbled on addprefix a directive that allows me to add only the filename of each src file I add to my project.

Assuming you have the files
and all obj files go in ./obj/
and your target executable is ./execfile

CC        =g++
CFLAGS =-c -Wall
INCLUDE =-I./include
OBJDIR =obj/
OBJLIST = file1.o file2.o file3.o
OBJECTS = $(addprefix $(OBJDIR), $(OBJLIST) )


execfile: $(OBJECTS)
[TAB]$(CC) $(LDFLAGS) $(OBJECTS) -o $@

$(OBJECTS): obj/%.o: src/%.cpp
[TAB]$(CC) $(CFLAGS) $? -o $@ $(INCLUDE)

[TAB]rm -rf obj/*.o
obviously, replace [TAB] with the actual tab character(\t).