MWSERVICE

Section: MidWay Programmer's Manual (3C)
Updated: DATE
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NAME

- MidWay service routines

SYNOPSIS

#include <MidWay.h>

int functionname(mwsvcinfo * msi);

DESCRIPTION

This is the prototype for writing service routines in C. A function must be registered as a MidWay service routine with mwprovide() where you give what name it should be announced with in the MidWay instance. You can either do mwprovide directly or by compile the C function into a shared library and use either mwserver() or give the shared library as an executable in the config file for mwd(). (see mwd.conf(4)).

The input parameters to the routine is given by the struct mwsvcinfo:

struct _mwsvcinfo {
  int handle;
  CLIENTID cltid;
  SERVERID srvid;
  char * data;
  int datalen;
  int flags;
  char service[MWMAXSVCNAME];

  time_t deadline; /* deadline here is pretty much a timeval struct. */
  int   udeadline; /* see gettimeofday(); */
};

Struct Description

handle: The handle returned by mwacall(). This is for info only.
cltid: The Client ID of the instance member that performed the mwacall().
srvid: If this call has been forwarded by another server thru the mwforward() call the id of the last server who did this is recorded here, UNASSIGNED (-1) otherwise.
data / datalen: The input data to the service function. datalen is never 0 even if 0 in the mw(a)call().
flags: The flags given in the client process to mw(a)call().
service: The service name used in the mw(a)call() or mwforward() call. This is needed in case you have registered the same C functions as service routines for multiple services.
deadline / udeadline: If the client had set a deadline with mwbegin() it is given here. You can compare with gettimeofday() is find out how much time remains. If you know that your routine will not complete in time you might as well return with ETIME immediately. This is optional, and is probably only needed in near realtime applications.

If your service routine need to return data or an application level return code you need to call mwreply() to do so. The C return shall only return success (0) or failure (!0) of the service call.

WARNINGS

EXAMPLES


int MYSERVICE (mwsvcinfo *msi)
{
        printf ("got a call from client %d, flags %#X, data=            msi->cltid, msi->flags, msi->data, msi->datalen);

        mwreply ("Hello Client!", 0, MWSUCCESS, 0, 0);
        return ;
};

BUGS

STANDARDS

NONE

Index

NAME

SYNOPSIS

DESCRIPTION

Struct Description

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Time: 11:18:50 GMT, October 24, 2000