This example handles host end of a named pipe for several other named pipe examples. Some return code checking has been omitted. Compile and run this program before running client programs to the named pipe.

#define INCL_BASE
#define INCL_DOSSEMAPHORES
#define INCL_DOSNMPIPES
#include <os2.h>
#include <stdio.h>
#include <string.h>

int main(VOID) {
CHAR     PipeName[256] = "\\PIPE\\EXAMPLE" ;     /* Pipe name */
HPIPE    PipeHandle    = NULLHANDLE;             /* Pipe handle */
HEV      hev           = NULLHANDLE;             /* Semaphore handle */
ULONG    ulBytes       = 0;                      /* Bytes read or written */
CHAR     message[256]  = "";                     /* Input/Output buffer */
APIRET   rc            = NO_ERROR;               /* Return code */

   rc = DosCreateNPipe(PipeName,                /* Name of pipe to create */
                       &PipeHandle,             /* Handle returned for pipe */
                       NP_ACCESS_DUPLEX,        /* Duplex pipe */
                       NP_WAIT |
                       NP_TYPE_MESSAGE |
                       NP_READMODE_MESSAGE |
                       NP_WMESG |               /* Write messages */
                       NP_RMESG |               /* Read messages */
                       0x01,                    /* Unique instance of pipe */
                       sizeof(message),         /* Output buffer size */
                       sizeof(message),         /* Input buffer size */
                       0L);                     /* Use default time-out */
   if (rc != NO_ERROR) {
     printf("DosCreateNPipe error: return code = %u\n",rc);
     return 1;
   }

   rc = DosCreateEventSem("\\SEM32\\PIPE\\EXAMPLE", &hev, 0L, 0L);
   /* Should check if (rc != NO_ERROR)  here... This semaphore is not
      always used.                                                     */

   rc = DosSetNPipeSem(PipeHandle,       /* Handle for pipe */
                       (HSEM) hev,       /* Handle of semaphore */
                       1L);              /* Used to distinguish among events */
   if (rc != NO_ERROR) {
     printf("DosSetNPipeSem error: return code = %u\n",rc);
     return 1;
   }

   printf("Waiting for connection to pipe %s...\n",PipeName);

   rc = DosConnectNPipe(PipeHandle);
   if (rc != NO_ERROR) {
     printf("DosConnectNPipe error: return code = %u\n",rc);
     return 1;
   }

   printf("\nCONNECTED\nWaiting for a message...\n");
   rc = DosRead(PipeHandle,            /* Handle of pipe */
                message,               /* Buffer for message read */
                sizeof(message),       /* Buffer size */
                &ulBytes);             /* Number of bytes actually read */
   if (rc != NO_ERROR) {
     printf("DosRead error: return code = %u\n",rc);
     return 1;
   }

   printf("\n\nMessage received was: %s\n\n", message);

   strcpy(message, "Thank you for your message!");
   rc = DosWrite(PipeHandle,           /* Handle of pipe */
                 message,              /* Buffer containing message to write */
                 strlen(message),      /* Length of message */
                 &ulBytes);            /* Number of bytes actually written */
   if (rc != NO_ERROR) {
     printf("DosWrite error: return code = %u\n",rc);
     return 1;
   }

   rc = DosCloseEventSem(hev);
   /* Should check if (rc != NO_ERROR)  here... */

   rc = DosDisConnectNPipe(PipeHandle);
   /* Should check if (rc != NO_ERROR)  here... */

   return NO_ERROR;
}