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EvmSrvStart(3)


NAME

  EvmSrvStart, EvmSrvMessageGet - Event service functions


SYNOPSIS

  #include <evm/evm.h>

  EvmStatus_t EvmSrvStart(
	  char *service_name,
	  char *arg_string,
	  EvmTransport_t *transport,
	  EvmConnection_t *connection );

  EvmStatus_t EvmSrvMessageGet(
	  EvmConnection_t connection,
	  EvmEvent_t *event,
	  char **msg,
	  char **errmsg,
	  EvmInt32_t *info );


OPERANDS

  service_name
      The name for this service. It  must be a service declared in the EVM
      daemon configuration file.

  arg_string
      If this operand is not NULL, it is written to the connection when the
      service is started.

  transport
      This specifies the type of connection to be made to the daemon. You
      usually should set this argument to NULL for the default connection to
      the local daemon. For remote connection, set it to the address of an
      EvmTransport_t structure, transport, initialized in the following
      manner:
	   char *hostname = "yoursys";
	   transport.type = EvmTRANSPORT_TCPIP;
	   transport.data.tcpip.portNumber = -1;
	   transport.data.tcpip.hostName = hostname;

  connection
      For EvmSrvStart() this is the return operand. The calling routine
      should pass this value to EvmConnDestroy() when it is done with the
      connection.

      For EvmSrvMessageGet() this is the service connection that will be read
      for a message.

  event
      If this operand is not NULL on return, it contains an EVM event
      returned by the service.

  msg If this operand is not NULL on return, it contains a character string
      returned by the service.

  errmsg
      If this operand is not NULL on return, it contains an error message
      character string returned by the service.

  info
      If this operand is not NULL on return, it contains numeric information
      returned by the service.


DESCRIPTION

  The EvmSrvStart() routine creates a service connection to the EVM daemon,
  requesting that the service identified as service_name be started. If the
  service is known to the daemon, it is started as a child process of the
  daemon, and the connection is transferred to the service process. If the
  arg_string is not NULL, the function then appends a newline character to it
  and writes it to the connection.

  The EvmSrvMessageGet() routine reads a single EVM service protocol message
  from the service connection identified by connection and returns it to the
  caller. The message may be a procedural protocol message, indicating that
  the service has started or terminated, or it may carry data. Procedural
  messages are handled by the API function. Data messages may be any one of
  the following:

    ·  An EVM event returned to the caller in event

    ·  A character string returned to the caller in msg

    ·  An error character string returned to the caller in errmsg

  In each of these cases, the data will be returned to the caller only if the
  address passed to the function as the corresponding argument is not NULL.

  The function returns a non-null value in at most one of these return
  arguments, and sets the others to NULL. If the incoming message does not
  include data (for example, if it is a protocol message indicating that the
  service is terminating) all three of the arguments are set to NULL.

  The message may carry one information item, which is returned if info is
  not NULL. This value is used in the service termination protocol message to
  indicate the service process's exit code.


NOTES

  This routine is not currently supported for general use.


RESTRICTIONS

  None


RETURN VALUES

  EvmERROR_NONE
      A data message was received, and is available in one of the three data
      return arguments, if a non-null pointer was supplied as the appropriate
      argument.

  EvmERROR_SERVICE_TERMINATED
      The service indicated that it was terminating. If the caller passed a
      non-null data argument, the service process's exit code is returned in
      the info operand.

  EvmERROR_EOF
      The service connection was closed by the service before a service
      termination message was received. This value is returned if the caller
      continues to attempt the call after the service has been terminated.


ERRORS

  None


LIBRARY

  EVM Support Library (libevm.so, libevm.a)


FILES

  None


SEE ALSO

  Commands: evmget(1)

  Routines: EvmConnDestroy(3)

  Files: evmdaemon.conf(4), kevm(7)

  Event Management: EVM(5)

  Event Connection: EvmConnection(5)

  EVM Events: EvmEvent(5)

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