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Date: Tue, 02 May 2006 12:16:44 -0700
From: Konstantin Shvachko <shv@yahoo-inc.com>
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To: hadoop-dev@lucene.apache.org
Subject: Re: C API for Hadoop DFS
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I think this a very important issue raised by David.

IMO __ALL__ functions should return an integer value indicating success 
(=0) or failure (<0).
Unless we want to use C style Exceptions, otherwise we won't be able to 
identify what went
wrong if anything.
NULL or bool is not enough in most cases, since we need to distinguish 
e.g. between
timeout (when we retry) and "file not found" cases.
The actual return objects should be passed as outputs parameters.
E.g.
dfsFS dfsConnect(char *host, tPort port);
will become
tCompletionCode dfsConnect(char *host, tPort port, dfsFS fileSystem );
where tCompletionCode could be integer for now. Or we can define a structure
{ int errCode; char *errDescription; }
to return the actual error descriptions along with the error code.

--Konstantin

Devaraj Das wrote:

>>Do dfsConnect and dfsOpenFile return NULL on failure?
>>    
>>
>Yes.
>
>  
>
>>Shouldn't dfsSeek, dfsRename, dfsCreateDirectory and 
>>dfsSetWorkingDirectory each have a return value to indicate success or 
>>failure?  Or are they assumed to never fail?
>>    
>>
>Yes these functions should have return values. I will update the API spec.
>Thanks for pointing this out.
>
>-----Original Message-----
>From: David Bowen [mailto:dbowen@yahoo-inc.com] 
>Sent: Monday, May 01, 2006 8:13 AM
>To: hadoop-dev@lucene.apache.org
>Subject: Re: C API for Hadoop DFS
>
>
>I'm curious about error handling. 
>
>Do dfsConnect and dfsOpenFile return NULL on failure?
>
>Shouldn't dfsSeek, dfsRename, dfsCreateDirectory and 
>dfsSetWorkingDirectory each have a return value to indicate success or 
>failure?  Or are they assumed to never fail?
>
>- David
>
>
>
>
>
>  
>