CODEWITHSUNDEEP
windowsgo
user626528
user626528

Reputation: 14418

Is it possible to open a file allowing another processes to delete this file?

It seems the default os.Open call allows another processes to write the opened file, but not to delete it. Is it possible to enable deletion as well? In .NET this can be done using FileShare.Delete flag, is there any analog in Go?

Upvotes: 2

Views: 2172

Answers (1)

thwd
thwd

Reputation: 24848

os.Open will get you a file descriptor with flag O_RDONLY set; that means read only. You can specify your own flag by using os.OpenFile

O_RDONLY int = syscall.O_RDONLY // open the file read-only.
O_WRONLY int = syscall.O_WRONLY // open the file write-only.
O_RDWR   int = syscall.O_RDWR   // open the file read-write.
O_APPEND int = syscall.O_APPEND // append data to the file when writing.
O_CREATE int = syscall.O_CREAT  // create a new file if none exists.
O_EXCL   int = syscall.O_EXCL   // used with O_CREATE, file must not exist
O_SYNC   int = syscall.O_SYNC   // open for synchronous I/O.
O_TRUNC  int = syscall.O_TRUNC  // if possible, truncate file when opened.

None of these modes, however, will allow you to have multiple writers on a single file. You can share the file descriptor by exec-ing or fork-ing but naively writing to the file from both processes will result in the OS deciding how to synchronise those writes -- which is almost never what you want.

Deleting a file while a process has a FD on it doesn't matter on unix-like systems. I'll go ahead and assume Windows won't like that, though.

Edit given the tag and @Not_a_Golfer's excellent observations:

You should be able to pass syscall.FILE_SHARE_DELETE as a flag to os.OpenFile on Windows, if that is what solves your problem.

If you need to combine several flags you can do so by or-ing them together:

syscall.FILE_SHARE_DELETE | syscall.SOME_OTHER_FLAG | syscall.AND_A_THIRD_FLAG

(note, however, that it's up to you to build a coherent flag)

Upvotes: 6

Related Questions