EvmSrvStart(3) Library Functions Manual EvmSrvStart(3)
NAME
EvmSrvStart, EvmSrvMessageGet - Event service functions
LIBRARY
EVM Support Library (libevm.so, libevm.a)
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
The name for this service. It must be a service declared in the EVM daemon configuration file. If this parameter is not NULL, it is
written to the connection when the service is started. 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 EvmTrans-
port_t structure, transport, initialized in the following manner: char *hostname = "yoursys"; transport.type = EvmTRANSPORT_TCPIP; trans-
port.data.tcpip.portNumber = -1; transport.data.tcpip.hostName = hostname; For EvmSrvStart() this is the return parameter. 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. If this parameter is not NULL on return, it
contains an EVM event returned by the service. If this parameter is not NULL on return, it contains a character string returned by
the service. If this parameter is not NULL on return, it contains an error message character string returned by the service. If
this parameter 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
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 appro-
priate argument. 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 parameter. 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
FILES
None
SEE ALSO
Commands: evmget(1)
Routines: EvmConnDestroy(3)
Files: evmdaemon.conf(4)
Event Management: EVM(5)
Event Connection: EvmConnection(5)
EVM Events: EvmEvent(5)
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EvmSrvStart(3)