https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92836
--- Comment #13 from Janne Blomqvist <jb at gcc dot gnu.org> ---
To clarify my previous message, instead of
inquire(..., exist=exist)
if (exist) then
open(...)
else
! Handle file not existing
end if
you can do
open(..., status='old', iostat=stat)
if (stat /= o) then
! Handle file not existing
end if
If you open a file with status='old', then opening the file will fail if it
doesn't exist, and thus there is no race between checking whether the file
exists with inquire and trying to open it.
Similarly, if you want to make sure that the file is created, i.e. that it
doesn't exist previously, instead of doing
inquire(..., exist=exist)
if (!exist) then
open(...)
else
! Handle if the file does exist
end if
You should do
open(..., status='new', iostat=stat)
if (stat /= 0) then
! Handle file existing
end if
With status='new', the file will be created and opened with O_CREAT|O_EXCL
which is guaranteed to be atomic.
