F_OK seems to be better than R_OK because we want to check file existence (not read permission) before creating the relation file with the path later.
2018-05-17 17:09 GMT+08:00 Michael Paquier <mich...@paquier.xyz>: > On Thu, May 17, 2018 at 04:09:27PM +0800, Paul Guo wrote: > > Previous code uses BasicOpenFile() + close(). > > > > access() should be faster than BasicOpenFile()+close() and access() > > should be more correct since BasicOpenFile() could fail for various > > cases (e.g. due to file permission, etc) even the file exists. > > Failing because of file permissions would be correct. There have been > cases in the past, particularly on Windows, where anti-virus softwares > wildly scan files, causing EACCES on various points of the data folder. > > > access() is supported on Linux/Unix. I do not have a Windows dev > > environment, but MSDN tells me that access() is supported on Windows also > > and there have been access() call in the workspace, so I assume there is > no > > portability issue. > > Yes, access() is spread already in the core code. > > - fd = BasicOpenFile(rpath, O_RDONLY | PG_BINARY); > > - if (fd >= 0) > + if (access(rpath, F_OK) == 0) > > What you are looking for here is R_OK, no? > -- > Michael >
