My Tech notes: May 2009

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Pointers and Arrays materials Explained for C beginners

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Wednesday, May 27, 2009

apsscresults 10th Class results ssc 2009 of AP Board

Andhra Pradesh State Board SSC Results 2009 announced today (27-May-09) by 10.45 am. There is lot of rush for those sites, Results will be available on the following sites: I have tried to give direct links for results, good luck to students.

Results direct links from manabadi ssc
SSC results on SMS from manabadi
  2. Indiaresults
  3. Bharat student
Results direct links from
  1. AP SSC REGULAR results 09
  2. AP SSC PRIVATE Results
  3. AP OSSC REGULAR results
  4. AP OSSC PRIVATE results
Sakshi Results
Sakshi Results. Ceep 2009 Results · Inter Second Year 2009 Results · Inter First Year 2009 Results.

Results direct links from provides you Andhra Pradesh examination results like SSC Results , Inter Results, MCA Results, ICET Results, MBA Results, EAMCET Results, ...

manabadi, andhraeducation, schools9, pratibhaplus, bharatstuden, manabadi, results.sakshi, schools9, manaba, manbadi, apsscresults, apssc, apresults, manabadi, sscresults, ap ssc , andhraeducation, pratibhaplus, manabadi, bharatstudent, bharathstudent , manabadi, indiaresults, deccan post, aarvy, vidyavision, results.sakshi, manabadi, manabadi ssc, aponline, maabadi, 10th class , esevaonlin,ushasri, manabadi, schools9, vidyavision, bharatstudent

Tuesday, May 26, 2009

C Traps & Pitfalls Book PDF Online by Andrew Koenig

C Traps & Pitfalls Book PDF Online by Andrew Koenig
C Traps and Pitfalls is a slim computer programming book by former AT&T researcher and programmer Andrew Koenig, its first edition still in print in 2005, which outlines the many ways in which beginners and even sometimes quite experienced C programmers can write poor, malfunctioning and dangerous source code.

It evolved from an earlier technical report published internally at Bell Labs, but is now available online in pdf form.

Happy coding.

Tuesday, May 12, 2009

Higher Secondary Kerala hse kerala Results Links

Today vhse kerala HSE Kerala DHSE Kerala hseresults 2009 Plus Two Kerala results are declared, students are finding difficult to get results as official sites are coming down, due to hevay loads, For those students here are some direct links and email registration links.

The result will be made available with the joint efforts of Kerala education board and the National Informatics Centre and to be published on
Arrangements have also been made at couple of hundred Akshaya Centres to provide the result where internet connectivity is a problem.
here are direct links for email Registration
DHSE (Plus Two) Results 2009

VHSE Results 2009

Schools can download the results of all their students. For students and schools who register on, the results would be sent to their e-mail ids soon after the results are declared.

VHSE Results 2009
Likely to be announced on 12 May 2009.
plus 2 Results 2009
Likely to be announced on 12 May 2009.

Kerala HSE Results 2009, DHSE Plus Two, VHSE Exam Results, Kerala. Government of Kerala Higher Secondary Examination Results 2009. Kerala Higher Secondary Result HSE 2009 - +2 Results hse kerala, higher secondary, vhsc kerala, hseresult, higher secondary education

Friday, May 8, 2009 PUC Exam Results 2009

Government of Karnataka KARNATAKA EXAMINATIONS AUTHORITY will declare PUC Exam Results 2009 by tomorrow
Likely to be declared on 09/05/2009 at 3:30pm

check you Karnataka PUC Exam Results 2009 at


Find Karnataka PUC Results,PUC Exam Results 2008, Karnataka PUC Results 2008, Karnataka Pre University Results,PUC Results only on

PUC Results 2009, Karnataka

PU Education Department, Karnataka will be announcing the PUC Results 2009 on 9th May 2009.

2 puc results, 2nd puc results, 2nd puc results 2009, cet exam results, karnataka puc results, Karnataka Results, Karnataka SSLC Results 2009, puc results 2009, puc results karnataka Karnataka PUC Results | PUC Exam Results 2008 | Karnataka PUC Results 2008 | Karnataka PUC results 2008 | PUC Results

Wednesday, May 6, 2009

Use of Select() System Call In Linux To make a non-blocking connect()

About Select system call
The  select() function shall examine the file descriptor sets whose addresses are passed in the readfds, writefds,
       and errorfds parameters to see whether some of their descriptors are ready for reading, are ready for  writing,  or
       have an exceptional condition pending, respectively.
  int select(int nfds, fd_set *restrict readfds,
              fd_set *restrict writefds, fd_set *restrict errorfds,
              struct timeval *restrict timeout);
There are many usages of select() system call, Here is one usage in networking applications, The use of select system call is to make non-blocking call in Linux.
how to make a non-blocking connect() in Linux

1. create socket using socket(),

2. set the file descriptor to non-blocking mode using fcntl(2)
   fnctl (fd, SETFL, fcntl(fd, GETFL) | O_NONBLOCK)

3. call connect() - since you have set the socket to non-blocking, it will
return right away with a result of EINPROGRESS.

4.  Now

   a) Go into a loop and keep calling connect() - as long as it
       has not completed it will return EALREADY (see man page for
       connect()).  This is simple but not a good solution. check below solution
       using select to avoid loop wait.
   b) Use select(2), selecting the socket for write.  When the connect is
       finished, the select should return and show the socket as writeable.
       Using select() can be tricky, but will be more efficient, since
       select() will block until the connect has finished and you are not
       wasting CPU in a tight loop.

       /* No loop required */
       fd_set write_set;
       FD_SET(write_set, fd);
       select (fd+1, 0, write_set, 0, 0);

File descriptor masks of type fd_set can be  initialized  and  tested  with  FD_CLR(),  FD_ISSET(),  FD_SET(),  and
     FD_SET(fd,  fdsetp)  shall add the file descriptor fd to the set pointed to by fdsetp. If the file descriptor fd is
       already in this set, there shall be no effect on the set, nor will an error be returned.
     FD_ZERO(fdsetp) shall initialize the descriptor set pointed to by fdsetp to the null set. No error is  returned  if
       the set is not empty at the time FD_ZERO() is invoked.
 The  original  Standard  can  be  obtained  online at

Tuesday, May 5, 2009

Working With Linux Patch 10 Step Guide

What is Linux patch ?
Here is patch description from Linux Man pages.
       patch - apply a diff file to an original

       patch [options] [originalfile [patchfile]]

       but usually just

       patch -pnum <patchfile

       patch  takes  a patch file patchfile containing a difference listing produced by the diff program and applies those
       differences to one or more original files, producing patched versions.  Normally the patched versions  are  put  in
       place  of the originals.  Backups can be made; see the -b or --backup option.  The names of the files to be patched
       are usually taken from the patch file, but if there√Ęs just one file to be patched it can specified on  the  command
       line as originalfile.

How Linux patch works?
Here is short explanation about How to use patches in linux.
Working with Patch 10 step Guide.
  1. mkdir patch_test
  2. cd patch_test/
  3. mkdir old
  4. cd old
  5. create   file1.txt and file2.txt
  6. cd .. ; mkdir new
  7. cp file.txt and file2.txt == Now change both or any files to create patch
  8. cd .. ; ls // new and old dir here
  9. diff -Naur old new > learn.patch  ==Your patch is ready.
  10. patch -p0 < learn.patch  == apply patch to old folder; you should be above old dir
How to Reverse patch applied?
In order to reverse the patch applied run following command.
patch -p 1 -R < learn.patch

Monday, May 4, 2009

Creation of Static Libraries In Linux Simple Steps

Here is real time example of creation of static library and its usage, explained in simple steps.
Creation of static library with example

Creation of Static Libraries In Linux Simple Steps

1. Create Test  Directory
  Create working test directory as: /home/test/so
 2. Choose Library Files
   library file name: add.c
     int add(int a, int b)
         return (a+b);
3. Compile
Now Compile Static Library with -shared option
   gcc -c add.c
   gcc -shared -o add.o
4. Usage of Static Library
 Here is example application uses this library.
   filename: main.c
   int main(void)
      printf("result: %d", add(1,2));
      return 0;
5. Compile Example Code
  gcc main.c -o main -L  <path where the library file is there, in our example it is> -l add
       (in last option -l add we have to specify library name. name of the library is, removing the "lib"
         from libadd. i.e. how gcc takes.)
   example: gcc main.c -o main -L /home/test/so -ladd
6. export LD_LIBRARY_PATH=<directory where your .so file is>
    if you copy the .so file to /lib  directory no need to set this environment variable

Tags static library, Linux, My Notes, C Programs, Embedded Linux.