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 and 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 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 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 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

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

GE_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 GE_CELL, if it is set.

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

GE_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.

GE_QMASTER_PORT
    If set, specifies the tcp port on which the ge_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 will fail if:

  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() will fail if:

  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() will fail if:

  DRMAA_ERRNO_NO_ACTIVE_SESSION
Failed because there is no active session.

  DRMAA_ERRNO_DRMS_EXIT_ERROR
DRM system disengagement failed.

SEE ALSO