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

       SGE_ROOT       Specifies the location of the Grid Engine standard
                      configuration files.

       SGE_CELL       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.


       SGE_DEBUG_LEVEL
                      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.

       SGE_QMASTER_PORT
                      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:

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

       DRMAA_ERRNO_DRM_COMMUNICATION_FAILURE
              Could not contact DRM system for this request.

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

       DRMAA_ERRNO_INVALID_ARGUMENT
              The input value for an argument is invalid.

       The drmaa_init() function can fail with:

       DRMAA_ERRNO_INVALID_CONTACT_STRING
              Initialization failed due to invalid contact string.

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

       DRMAA_ERRNO_DRMS_INIT_FAILED
              Initialization failed due to failure to init DRM system.

       DRMAA_ERRNO_ALREADY_ACTIVE_SESSION
              Initialization failed due to existing DRMAA session.

       DRMAA_ERRNO_NO_MEMORY
              Failed allocating memory.

       The drmaa_exit() function can fail with:

       DRMAA_ERRNO_NO_ACTIVE_SESSION
              Failed because there is no active session.

       DRMAA_ERRNO_DRMS_EXIT_ERROR
              DRM system disengagement failed.

SEE ALSO

       drmaa_submit(3).



SGE 8.1.3pre             $Date: 2008-07-08 09:10:04 $         drmaa_session(3)