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drmaa_session(3) Grid Engine DRMAA drmaa_session(3)

NAME

drmaa_init, drmaa_exit - Start/finish Grid Engine DRMAA session

SYNOPSIS

#include "drmaa.h"

int drmaa_init(
const char *contact,
char *error_diagnosis,
size_t error_diag_len


);




int drmaa_exit(




char *error_diagnosis,
size_t error_diag_len






);






DESCRIPTION




drmaa_init()


The drmaa_init() function initializes the Grid Engine DRMAA API
    library for all threads of the process and creates a new DRMAA session. This
    routine must be called once before any other DRMAA call, except for
    drmaa_version(3), drmaa_get_DRM_system(3), and
    drmaa_get_DRMAA_implementation(3). Except for the above listed
    functions, no DRMAA functions may be called before the drmaa_init() function
    completes. Any DRMAA function which is called before the drmaa_init()
    function completes will return a DRMAA_ERRNO_NO_ACTIVE_SESSION error.
    Contact is an implementation dependent string which may be used to
    specify which Grid Engine cell to use. If contact is NULL, the
    default Grid Engine cell will be used. In the 1.0 implementation
    contact may have the following value:
    session=session_id. To determine the session_id,
    the drmaa_get_contact(3) function should be called after
    the session has already been initialized. By passing the
    session=session_id string to the drmaa_init() function,
    instead of creating a new session, DRMAA will attempt to reconnect to
    the session indicated by the session_id. The result of
    reconnecting to a previous session is that all jobs previously
    submitted in that session that are still running will
    be available in the DRMAA session. Note, however, that jobs which
    ended before the call to drmaa_init() may not be available or may
    have no associated exit information or resource usage data.






drmaa_exit()


The drmaa_exit() function closes the DRMAA session for all threads
    and must be called before process termination. The drmaa_exit() function may
    be called only once by a single thread in the process and may only be called
    after the drmaa_init() function has completed. Any DRMAA function, other
    than drmaa_init(3), which is called after the drmaa_exit() function
    completes will return a DRMAA_ERRNO_NO_ACTIVE_SESSION error.


The drmaa_exit() function does necessary clean up of the DRMAA
    session state, including unregistering from the qmaster(8). If the
    drmaa_exit() function is not called, the qmaster will store events for the
    DRMAA client until the connection times out, causing extra work for the
    qmaster and consuming system resources.


Submitted jobs are not affected by the drmaa_exit() function.








ENVIRONMENTAL VARIABLES



  

  
Specifies the location of the Grid Engine standard configuration
    files.

  

  
If set, specifies the default Grid Engine cell to be used. To address a
      Grid Engine cell Grid Engine uses (in the order of precedence):
    

  






The name of the cell specified in the environment
  variable SGE_CELL, if it is set.

The name of the default cell, i.e. default.









  

  
If set, specifies that debug information should be written to stderr. In
      addition the level of detail in which debug information is generated is
      defined.

  

  
If set, specifies the tcp port on which the sge_qmaster is expected to
      listen for communication requests. Most installations will use a services
      map entry instead to define that port.








RETURN VALUES


Upon successful completion, drmaa_init() and drmaa_exit() return
    DRMAA_ERRNO_SUCCESS. Other values indicate an error. Up to
    error_diag_len characters of error related diagnosis information is
    then provided in the buffer error_diagnosis.






ERRORS


The drmaa_init() and drmaa_exit() functions can fail with:



  

  
Unexpected or internal DRMAA error, like system call failure, etc.

  

  
Could not contact DRM system for this request.

  

  
The specified request is not processed successfully due to authorization
      failure.

  

  
The input value for an argument is invalid.




The drmaa_init() function can fail with:



  

  
Initialization failed due to invalid contact string.

  

  
Could not use the default contact string to connect to DRM system.

  

  
Initialization failed due to failure to init DRM system.

  

  
Initialization failed due to existing DRMAA session.

  

  
Failed allocating memory.




The drmaa_exit() function can fail with:



  

  
Failed because there is no active session.

  

  
DRM system disengagement failed.








SEE ALSO


drmaa_submit(3).







  

    $Date: 2008-07-08 09:10:04 $
    SGE 8.1.3pre