topic Hi Stan, in Intel® MPI Library

MPI IO - simple question

stansy — Sun, 23 Sep 2012 18:36:41 GMT

Hi,

How do I check if a file exists and has been successfully opened. MPI::File::Open function suspends my program.

Thanks,

Stan

Hi Stan,

James_T_Intel — Mon, 24 Sep 2012 15:08:53 GMT

Hi Stan, If MPI_File_open were returning, you could use the return code to determine if the file exists or not. Since your program isn't getting past MPI_File_open, you'll need to use a non-MPI mechanism to do this. In C++, I would likely try to open the file (closing it immediately afterwards), as this is a portable method. You can check the return values from the open attempt. There are also non-portable methods that can check without opening the file. Sincerely, James Tullos Technical Consulting Engineer Intel® Cluster Tools

Hi James,

stansy — Mon, 24 Sep 2012 18:33:09 GMT

Hi James, Many thanks for the comprehensive answer. Because I use C + + interface I adopted _access_s () function. I think it is safe: MPI::File fin = MPI::FILE_NULL; if(_access_s( fname, 0 ) == 0) fin = MPI::File::Open(MPI::COMM_WORLD, fname, MPI::MODE_RDONLY, MPI::INFO_NULL); if(fin != MPI::FILE_NULL){ something, something .... } Width regards, Stan