Programming question
Ben Pfaff
pfaffben@msu.edu
21 Jan 2001 04:13:39 -0500
Edward Glowacki <glowack2@msu.edu> writes:
> On Fri, 19 Jan 2001, Don Chorman wrote:
> > I am writing a program in C++, and I need it to write to
> > a new file. I'm know how to do this part, but I want to
> > avoid overwriting files, or atleast warn the user that a
> > particular file exists. Can I code this in C++?
>
> The quick and relatively useless answer is: Yes, and Yes.
>
> There are probably a dozen different ways to check to see if a file
> exists. "stat()" is one such C call you can use, there might be
> better ones for C, and for C++ there may be some others, but at
> least its a place to start.
stat() is a poor way to do this, because there is a race
condition:
Your Program Another Program
------------ ---------------
stat() - is file `foo' here?
no, there isn't...
create file `foo'
create (overwrite) file `foo'
--
"Let others praise ancient times; I am glad I was born in these."
--Ovid (43 BC-18 AD)