Mostly, I remember important e-mails by remembering the time frame (or any nearby events) during which I received the email. For example, all  conversations regarding first assignment of a course happened during the semester beginning time-frame. So, I would like to mark one e-mail which I received at the semester beginning. When I click on that marked email, it should not open that email. It should show the list of emails in Inbox received during the semester beginning time-frame and the cursor/pointer should point to that email. So, I can find emails of the first assignment just above the marked email.

In GMail, “Starred” items act as “bookmarks”. When I click on an email in “Starred emails”, it will open that e-mail. The new feature that I want is “location markers”. “Searching emails” does not work for me always as I don’t remember the keywords many times, but I remember the time frame during which I received the email. Using “after” and “before” while searching in GMail solves the problem to some extent, but not completely.

If this feature is implemented in GMail, it would be really nice. May be, this feature is implemented in different form, but I am not aware.

In C/C++, functions can be written to take variable no. of arguments. Examples are printf, sprintf, snprintf etc. The prototype of printf functions looks like int printf(const char *format, …). These functions internally use macros such as va_start, va_arg, va_end etc to get the passed parameters. But, I have observed that for every function like printf, there is another similarly defined function which takes va_list instead of … . For example, vprintf is similar to printf and has int vprintf(const char *format, va_list ap) prototype. In the same way, vsprintf and vsnprintf are also defined. Till now, I did not know the reason and used to think of it as an unnecessary wrapper.

For example, if a wrapper called myprintf needs to be written over printf

int myprintf(const char* format, …){

va_list ap;

va_start(ap,format);

???????

va_end(ap);

}

In the above code, I can not put ‘printf’ in place of ??????. Because printf is expecting variable arguments (like i, j , l) and not va_list dataype. So, in place of ??????, I should call vprintf which takes va_list.

So, I observed that it is a good practice to write 2 functions in case of variable number of arguments. One which takes variable no. of arguments as … and the other one taking va_list. An example is given below.

void vfunction (char * format, va_list ap){

/*This function does the actual work*/

}

void function(char* format, …){

/*This function just redirects to vfunction which does the work */

va_list ap;

va_start(ap,format);

vfunction(format, ap);

va_end(ap);

}

I recently learnt that plus addressing is supported in GMail. I feel this is a nice feature. If plus addressing is supported, even if we send a mail to user+office@gmail.com, it will be delivered to user@gmail.com. But, for user, it will be easy to set filters based on the extra information (+office). User can give different email addresses (user+office, user+maths, user+studies etc.) to others for different purposes.

This feature (but as minus addressing) is supported in Yahoo mail also (only in Yahoo Mail Plus). You can read more information about plus addressing here.

In web based e-mail services like yahoo mail & gmail, I always feel 1 feature is missing. That is setting timer to send mails. Suppose, if tomorrow is my friend’s birthday, I will write an email and set a timer to deliver the email at night 12′ clock. I don’t have to be awake till 12′ clock to wish him.

In the view part, only change is “Drop down” should be provided at the send button to select the time.

I know we can achieve this using schedulers present in our machines. But, feature like this in web based mail services will reach more audience. If this option is provided in yahoo or gmail, that will be very nice.

When I converted a file from EBCDIC format to ASCII format using an online tool, there are many non-printable characters in the ASCII file. So, this ASCII file is completely unreadable. So, I followed the below steps to make it readable.

1) Find hexa value of that non-printable character. Move your cursor to that character and press ‘ga’.

2) In escape mode, execute this ‘:%s/\%x85/\r/gc’. In my case, hexadecimal value of that non-printable character is 85. I replaced that with ‘\r’.

Some characters like ‘Ctrl+M’ can be printed by ‘Ctrl+v’ + ‘Ctrl+M’. But, in my case, 0×85 is that non-printable character and could not print it using ‘Ctrl+v’.

In our makefiles, we call shell commands like printf. Makefiles are internally executing that command through /bin/sh like /bin/sh -c printf hi. In my newly installed solaris machine, I have observed that some commands [printf] are running very slow. Then, I have seen the main reason as printf is not built-in function in the shell. But, in /bin/bash, it is built-in. The same command is running very fast in bash. As I know, /bin/bash [BASH] is advanced than /bin/sh [Bourne shell]. So, I have created a soft link from /bin/bash to /bin/sh. Now, whenever I execute /bin/sh, automatically bash will be executed. As of now, I did not get any problem with this approach and it seems bash has many built-in commands and fast.

In Unix systems, commands are hashed for performance reasons [man hash]. Today, I got a problem related to this and wasted so much time for resolving. In my solaris machine, patch command is in /usr/bin/patch and its version is very old. So, I have installed a new patch version using pkgadd and it has installed patch command in /usr/local/bin/. In PATH variable, /usr/local/bin/ is before /usr/bin directory.  So, `which patch` command is showing /usr/local/bin/patch. But, when I execute patch on command prompt, it is executing old version of patch [/usr/bin/patch]. After some time, I tried type command `type patch` and it is showing /usr/bin/patch is hashed. Then, I came to know about hash command in solaris. After rehashing, every thing started working fine.

Today, when trying to execute a test program on Vista, I got the above error. I have copied only executable and forgot to copy manifest file to the destination folder. So, I was getting the above error, when I tried to execute the executable. But, after copying manifest file also, this error did not go away. I have searched over the net for any clues, in many forums this issue is discussed, but all posts are talking about some manifest problem in Vista. But, somewhere I read that Vista caches the meta data. So, I touched the executable using touch command to change the last modified time[I use cygwin]. After that OS is able to recognize manifest file associated with executable and started working fine.

Yesterday, while using getpass* functions & passwd command in solaris, I found a bug. Type passwd command and press ctrl-z to stop that process and bring that process to foreground using fg command. Now, you can see your password while typing it. Basically, tty are settings are reset when you stop the process and bring it to foreground.

when I sent a mail to Sun Security Coordination Team [secure@security.Eng.Sun.COM], they said it was found internally recently and already raised as a bug http://bugs.opensolaris.org/bugdatabase/view_bug.do?bug_id=6443857 in OpenSolaris bug database. By mistake, as it is noted as security vulnerability in bug description, so it is not visible outside.

In gdb/dbx, we can see the variable using addresses. Suppose a structure [struct Box * b] is not deallocated but we are setting it to NULL i.e. b = NULL. We can not access that structure using b. But if we know the address pointed by b [we can get it using print b], we can access it like *(struct Box *) (0×4f2b2448) [assuming 0x4f2b2448 is the address that b points]. Obviously this is a very simple thing. But, I have used it for the first time. Similarly, when setting watchpoints over variables like watch b->length, if the control goes to some other place where this variable b is not in scope, that watchpoint will be deleted. [Atleast this happens in old gdb versions, I'm using SuSE 8]. So, in those cases you can put watch point over address so that it is accessible from anywhere. watch ((struct Box *)(0×4f2b2448))->length works fine.