IECore.Reader.create() call on an empty cob file results Ptex error message spam

**Version**: Cortex 10.4.8.0

### Description ###

When trying to create a reader for an empty cob file (and `IECoreImage` is loaded), stderr gets spammed with dozens of error messages like the following:

```
PtexReader error: read failed (EOF) PtexFile: /tmp/tmpznhadp6v.cob
```

While discussing the issue with @johnhaddon , we decided that simply skipping empty files would not be a good solution (as for some readers, those could be valid, and the potential of performance degradation), and that a better approach would be to try and get this sorted out on the OIIO side which is where the error messages are coming from.

Assigning this to @johnhaddon.

### Steps to Reproduce ###

1. Create an empty cob file (ex: `/tmp/tmpznhadp6v.cob`)
2. Run the following code:
```
import IECore
import IECoreImage

r = IECore.Reader.create( "/data/share/ivani/tmpznhadp6v.cob" )
```

You should be spammed with error messages of this sort:
```
PtexReader error: read failed (EOF) PtexFile: /tmp/tmpznhadp6v.cob
```

### Debug Log ###

<details>
<summary>Click to Expand</summary><p>



```
Python 3.7.12 (default, Dec  6 2021, 10:07:27) 
[GCC 9.3.1 20200408] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import IECore
>>> import IECoreImage
>>> 
>>> r = IECore.Reader.create( "/data/share/ivani/tmpr37o1ch2.cob" )
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
PtexReader error: read failed (EOF) PtexFile: /data/share/ivani/tmpr37o1ch2.cob
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IECore.Exception: Unable to load file '/data/share/ivani/tmpr37o1ch2.cob'!

```
</p>
</details>

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IECore.Reader.create() call on an empty cob file results Ptex error message spam #1364

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IECore.Reader.create() call on an empty cob file results Ptex error message spam #1364

Description

Description

Steps to Reproduce

Debug Log

Metadata

Metadata

Assignees

Labels

Type

Projects

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Development

Issue actions