Issuing an APPC Verb

The following procedure is required to issue a blocking APPC verb. In the sample code, the verb issued is MC_SEND_DATA.

Create a structure variable from the VCB structure that applies to the APPC verb to be issued.
```
#include <winappc.h>
    .
    .
struct mc_send_data  mcsend;
 
```
The VCB structures are declared in WINAPPC.H; one of these structures is:
```
mc_send_data
 
```
Clear (set to zero) the variables within the VCB structure.
```
memset( mcsend, '\0', sizeof( mcsend ) );
 
```
Assign values to the VCB variables that supply information to APPC.
```
mcsend.opcode = AP_M_SEND_DATA;
mcsend.opext = AP_MAPPED_CONVERSATION;
memcpy( mcsend.tp_id, tp_id, sizeof( tp_id ) );
mcsend.conv_id = conv_id;
mcsend.dlen = datalen;
mcsend.dptr = sharebufptr;
 
```
The values AP_MAPPED_CONVERSATION and AP_M_SEND_DATA are symbolic constants representing integers. These constants are defined in WINAPPC.H.
Invoke the APPC function. The only parameter is a pointer to the address of the structure containing the VCB for the desired verb.
```
APPC ( ( long ) (void FAR * ) &mcsend );
 
```
Use WinAsyncAPPC if you are running the application under Windows version 3.x.
To call WinAsyncAPPC:
```
HANDLE WINAPI WinAsyncAPPC (hWnd, 1pVCB)
 
```
When the asynchronous operation is complete, the application's window hWnd receives the message returned by RegisterWindowMessage with "WinAsyncAPPC" as the input string.

Use the variables that were returned by APPC.

if( mcsend.primary_rc != AP_OK ) 
/* Do error routine */
    .
    .
    .