RE: ECPG: inconsistent behavior with the document in “GET/SET DESCRIPTOR.”

Dear Kamura-san,

> Embedded SQL:
> ```
> EXEC SQL GET DESCRIPTOR d :desc_count1 = count, :desc_count2 = count;
> ```
> 
> Precompiled result:
> ```
> { ECPGget_desc_header(__LINE__, "d", &(desc_count2desc_count1));
> ```
> 
> Reported error by the compiler:
> ```
> bytea.pgc: In function 'main':
> 
> bytea.pgc:123:48: error: 'desc_count2desc_count1' undeclared (first use in this
> function)

Good catch, agreed that current result should be fixed.

> According to my analysis, the parser can accept multiple headers,
> but the output function cannot.
> See ECPGGetDescHeaderItems and output_get_descr_header().
> Therefore, it is thought that the variables were incorrectly concatenated,
> resulting in an error.
> 
> I feel even if multiple header items cannot be specified,
> invalid syntax should be detected by the precompiler, not the compiler.
> Attached patch fixes both parser and the documentation.
> After applying the patch, the above example can detect the invalid syntax
> by the precompiler anymore.

IIUC, there is another approach, allowing to specify multiple COUNT clause
in the SET/GET DESCRIPTOR. E.g.,

```
EXEC SQL GET DESCRIPTOR d :desc_count1 = count, :desc_count2 = count;
 -> set COUNT value to desc_count1 and desc_count2.
```

Do you have theory which one is better?

Best regards,
Hayato Kuroda
FUJITSU LIMITED