[Issue 17912] New: Add function to std.file for creating a temporary file with a name

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=17912

          Issue ID: 17912
           Summary: Add function to std.file for creating a temporary file
                    with a name
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: phobos
          Assignee: nobody at puremagic.com
          Reporter: issues.dlang at jmdavisProg.com

We previously added a function to std.stdio for safely creating a temporary
file with a name that could be closed and reopened (unlike
std.stdio.File.tmpfile, which has no name and is deleted when it's closed), but
it was removed due to the fact that it increased the size of hello world even
though it arguably shouldn't have:

https://issues.dlang.org/show_bug.cgi?id=14599

I propose that instead of waiting for the compiler to be improved to the point
that we can re-add scratchFile to std.stdio without increasing the size of hell
world, we add a function to std.file which creates a temporary file and returns
its name. It does have the downside that you have to reopen the file if you
want to use it with std.stdio.File, but it could optionally accept data like
std.file.write does so that it can be created with data rather than having to
create it and then reopen it to write to it.

And for many (most?) cases where you want a temporary file with a name to be
operating on, this arrangement would probably work better than getting a
std.stdio.File to write to anyway (e.g. a major use case is creating a
temporary file for unit tests where you need a file to read and write to using
its name).

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