UDF PROGRAMMERS MANUAL





 file_open (1) 
     UDF PROGRAMMERS MANUAL
     file_open (1)
 


 
  NAME  file_open




 SYNOPSIS  
 



 #include "libbase_udf.h"


 ByTe_2
     file_open
     (u_ByTe_4 Key, ByTe_1 *Ext, 
                       u_ByTe_2 Ver, ByTe_2 Byear, 
                       ByTe_2 Bday, ByTe_4 Bsec, 
                       ByTe_4 Bnsec, ByTe_2 Eyear, 
                       ByTe_2 Eday, ByTe_4 Esec, 
                       ByTe_4 Ensec ByTe_1 Status);


 




 INPUT DEFINITIONS  








 Key
     -
     UDF data key


 Ext
     -
     UDF file extension


 Ver
     -
     Version number


 Byear
     -
     Beginning year of requested data


 Bday
     -
     Beginning day of year of requested data


 Bsec
     -
     Beginning second of day of requested data


 Bnsec
     -
     Beginning nanosecond of second of requested data


 Eyear
     -
     Ending year of requested data


 Eday
     -
     Ending day of year of requested data


 Esec
     -
     Ending second of day of requested data


 Ensec
     -
     Ending nanosecond of second of requested data


 Status
     -
     Status data requested flag

 



 0
     -
     No status data will be requested from this UDF


 1
     -
     Status data will be requested from this UDF










  DESCRIPTION  
  file_open() attempts to a set of UDF header, data, and VIDF 
files.  The UDF definition being accessed is identified by Key 
and the files to be opened are those files which contain the start 
time Byear, Bday, Bsec, and Bnsec.  The 
last time to be accessed is also passed into the routine as Eyear, 
Eday, Esec, and Ensec.  This time may or may not
be included in the opened files.  If the routine cannot find a file
containing the beginning time then it will open the file which has
the earliest possible time within the range requested,  




 If status data is to be retrieved from this UDF then Status 
must be set to 1, otherwise it should be set to 0.  Under normal 
conditions Ext should be set to a NULL string.  Setting 
Ext to a non-NULL string will cause the file_open routine to 
attempt to open the appropriate named UDF header and data
files but with the string .Ext appended to it.  The file must 
exist in the current working directory.  Ver identifies the
version number to be assoicated with the open files.  By calling
file_open() for the same Key but with different values of
Ver it is possible to multiply open the UDF definition.




The file_open routine can be made to just open the VIDF 
by setting the external variable plot_package to 0.  This
is useful in instances where the VIDF alone is being accessed.
In most instances the VIDF will be online even when the Data
and Header files arn't.






  RETURN VALUE  
  On success, ALL_OKAY is returned, otherwise an error code is
returned.




  ERRORS  

 OPEN_EX_MALLOC  Error in obtaining memeory for UDF definition
 OPEN_PTR_MALLOC  Error in obtaining memeory for UDF pointers
 OPEN_EX_REALLOC  Error in enlarging memoryg for UDF definition
  




  APPLICABLE FORMATS  
  UDF V2.2, IDFS V2.1




  RESTRICTIONS  
The UDF database keeps file times only down to the millisecond level
so that the nanosecond of beginning second only is used down a resolution
of 1 millisecond.




  SEE ALSO  
ret_codes (1H)










 UDF V2.2
     July 31, 1999
     UDF V2.2
 










  

    
    TOC
    HOME