<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/108065>108065</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [flang][I/O] SNbone outputs data to stderr instead to a file
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            flang
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          pawosm-arm
      </td>
    </tr>
</table>

<pre>
    I was trying to observe how SNbone behaves when compiled with flang-new, and sadly, it exposed a seriously weird behavior. What I'm seeing is that this code https://github.com/ANL-CESAR/SNbone/blob/dc2c25d51af12933070fd559d933431dd146a035/src_makemesh/Export_Mesh.F90#L32

```
200 FORMAT(10I8)
210 FORMAT(1P,6(E13.6,1X))
OPEN(UNIT=File_Unit,IOSTAT=IOS,FILE='grid_tet_mesh.ascii')
WRITE(File_Unit,'("# Version 1.0 file format for CFE SN miniapp")')        ! Generic junk about the file type
WRITE(File_Unit,200) NumVertices,NumElements,NumVacuum
DO Vertex = 1,NumVertices
   WRITE(File_Unit,210) GlobalXYZ(Vertex,1),GlobalXYZ(Vertex,2),GlobalXYZ(Vertex,3)
END DO
DO Element = 1,NumElements
   WRITE(File_Unit,200) Conn(1,Element),Conn(2,Element),Conn(3,Element),Conn(4,Element)
END DO
DO Element = 1,NumVacuum
   WRITE(File_Unit,200) ElementsWithVacuumBCs(Element),LocalSurfaceIndex(Element)
END DO
CLOSE(File_Unit)
```
...does not result in data outputed into the `grid_tet_mesh.ascii` file, everything is dumped to `stderr` (and there is a lot of it!).

To reproduce:

```
$ ./src_makemesh/makemesh.x 30 30 30 0
```

A workaround to have actual data file:

```
$ ./src_makemesh/makemesh.x 30 30 30 0 2>grid_tet_mesh.ascii
```

To make use of the outputed file:

```
$ ln -s grid_tet_mesh.ascii inputmesh.ascii
$ ./src_processmesh/processmesh.x 1 1
```

</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJysVV1zozoP_jXOjaYMyCGBi1x0SdjJTDfZ2XQ_3vemY7ASvAuYsU3T_vszBtqTczbt7MXJMBDL0qNHsiwJa9WpJVqx-AOL1zPRu0qbVSfO2jY3wjSzQsvn1RbOwoIzz6o9gdOgC0vmkaDSZzjsCt0SFFSJR7JwrqiFUjedqknCWbkKjrVoTzctnRlmIFoJVsj62S-UA3rqtCUJAiwZpXtbP8OZlJEjotImgO-VcLBluGzAEnkOyoLzQlcpC6WWBJVznWX8lmHOMD8pV_VFUOqGYX67u7vJNofbLwzzkS3DvKh1wTCXJZYYyzgSxwhTzsNleJRxnMqU8zmPpIzmCxHymGFuTfnQiF_UkK0Y5punThv38IlsFeRpyJDfcWThmoW303sRTs-wxDCEfP_l0-09wyQKtwnDdNqJLnc-M8wWDJNNxIMFwyz64RVfdPefNzuGydfd9p7xda5qevjaKscw2-4P97deuN0fGGb59m7D-Jrh8mSUfHDkHjzxQNhSKYbLV8TvX7b3G4bJJdawnzBEhhy-kbFKtxAFIRxVTXDUphHOfyDLN3DYQaNaJbpuMEhHcJh-DCP4SC0ZVcLPvv0FotC9PzgawdxzR28TwTD0WLu--UbGqZIsw2zXN5uaGmrdtPomyr5vRpT13hN29ASMryGaFF6MBxUAuOorGnx9rHUh6h__-z_DZETyhzDElV3dw3f2-GuaN7s1rPevHKcALkm-xvQuyTEhmW5bXywMs8lsJDHJ8Q05f0M-_6f8Dwlfpv19ui-hfVeuGq0-ZNbX-CWXO12K-tCboyhp20qfv-Q9Utnd_vAvf-nVmxcEgdRkodUODNm-dqBakMIJ0L3rekcSVOv0UJRsEV67MIux9n3Tokcyz66a2pDsm46kb4psEVonyRivzDDxnc5VZMirCai1A30ET9NXU3DZKu41GOqMln1Jvoe93UUYziH4vRm9_A2egIfTE14HGN63cNbmlzC6bwfuvneDKF0v6jExQ7D_GRNAxjfX0vo2w3sNHgp6Sz5t_mheD-vPyNUt3Fi44hVU2_XuNxYX8XRGl2TtFNLFKniCCKKrLmdyxWXKUzGjVbTEOE2jBZ_PqlUhKJbz9BjHyOMyjZN0cUwXJZLkcpnO-UytMMR5mEZhlITLaB4kgqd8OY8KHiXRsRBsHlIjVB3U9WMTaHOaKWt7WkVhEi7iWS0Kqu0wwhGHYesbcbyemZU3uCn6k2XzsFbW2b8hnHL1MPdHi3jN4g9bhvmexeuXoT5m3I4l4TSM9Q2qtY7EUDhjpcx6U6_emcDe6fS56Yz-SaVjmA9BWIb5FMfjCv8KAAD__z5pjVs">