How to create a tempfile

Problem: Your code needs to create a file (and perform write/read operations on it probably) during its execution. In many cases, there are two requirements.
1. It should be unique, which means that you do not want to overwrite any existing files. Sometimes you even want exclusive access to that file to avoid race conditions.
2. The file is no longer needed when the program is done, thus you need to clean up after yourself.

Solution: The problem is similar to the malloc() and free() problem, therefore it is not surprising to see a solution similar to alloca() and smart pointers. A tempfile is a file which will be automatically deleted when it is closed or the program terminates.

Short answer: tmpfile() is the way to go. It confirms to a bunch of standards, including 4.3 BSD/C89/C99/POSIX. When you do not want to have the file automatically deleted, use mkstemp() instead, which also gives you some control over the file name.

Long story:
mkstemp() and mktemp() will create a temporary file while DO NOT delete it automatically. Besides, on the manual page of mktemp(), it says "never use mktemp()" and suggests mkstemp() to avoid a race condition.

You may also use mkdtemp() to create a temporary directory. Again, the caveat is that mkdtemp() is similar to mktemp(), i.e. the directory does not get garbage collected automatically.

tempnam() and tmpname() create a name for a temporary file, which does not conflict with existing files. The catch is that on their manual pages, you will see the "never use this function" label and mkstemp() and tmpfile() are suggested here again.

Tips:
1. Always read the notes and bugs sections on the manual pages.
2. Check out related functions in the "see also" section on the manual pages. There may be a better choice among them.

Revived!

Finally I reclaimed my blog. The username was simply yeshao but I tried with my previous email account which expired three years ago. I tried to reclaim my blog but blogger's policy does not allow me to do that besides sending a new password to my non-exist email account.

Today I noticed the error message when I failed to login was "username not found" instead of wrong password. Then I told myself that I should try with my favorate username and it worked after a few password tests.

The blog was created in 2003, probably before blogspot was acquired by Google. Now I have the option to hook up the blog with my gmail account, replacing the expired one. Yay!

I am gonna use this blog for technical posts and keep my msn/live space personal.

So glad that I get my blog back!

Update: blogspot was acquired by Google in Feb 2003 so my account was created after the acquisition but at that time Google had not integrated all its products with Google account. Actually gmail was released on April 1, 2004 which later backed up Google account.

Update 2: The next thing to reclaim is an email account which I do not know the answer to the security question yet.