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Re: 20030808:netcdf error number -31

>To: address@hidden
>From: Daniel Cohan <address@hidden>
>Subject: netcdf error number -31
>Organization: UCAR/Unidata
>Keywords: 200308081358.h78DwoLd017320

Hi Dan,

> I am running the Community Multiscale Air Quality (CMAQ) model on a Linux
> machine, and it frequently (but not always) is crashing with netCDF error 
> number
> -31.  The timing of the crashes is not consistent; for example, the following
> error messages are after the model had been outputting normally for 29 hours 
> of
> simulation.  I am running a modified version of CMAQ that outputs more netCDF
> output files than standard CMAQ, but I also sometimes get similar crashes with
> error -31 when running standard CMAQ. 
> 
> What do these errors mean, and how can I keep them from occuring?

You can find out what they mean by calling the netCDF function
nc_strerror() from C programs or the equivalent nf_strerror() function
from Fortran programs, giving the error as the only argument to the
functions.  They return a string that provides a human-readable error
message.

In the case of error -31, this might be the not-very-helpful "system
error", which indicates that the system-level write() call fails with
an error.  This could occur if you were writing to a full disk, there
was a media error, you were writing across a network connection and
the network link or the system at the other end of the link went
down, a disk write quota was exceeded, etc.  In other words, this
could occur from any error that might occur from a system-level
write() call.  You still might get more information by printing out
the string resulting from the nf_strerror(-31) call, because in the
case of a system error, it tries to determine which system error and
substitute an appropriate message, like "disk full", for the returned
error message string, if possible.

--Russ

> Thank you,
> Dan Cohan
> 
> 
>      Timestep written to CTM_CONC_BC      for date and time  2000225:110000
> NCVPT: : Input/output error
> 
> 
>      >>> WARNING in subroutine WRVARS <<<
>      Error writing variable NO2_PT343001    to file CTM_SENS_BC     
>      netCDF error number  -31