dx_setuio( )

Description | Cautions | Example | Errors

Name:	int dx_setuio(uioblk)
Inputs:	uioblk	DX_UIO structure
Returns:	0 if success
	-1 if failure
Includes:	srllib.h
	dxxxlib.h
Category:	miscellaneous function

Description

The dx_setuio( ) function allows an application to install a user I/O routine read( ), write( ), and lseek( ) functions. These functions are then used by the dx_play( ) and dx_rec( ) functions to read and/or write to nonstandard storage media.

The application provides the addresses of user-defined read( ), write( ) and, optionally, lseek( ) functions by initializing the DX_UIO structure. The application then installs the functions by invoking the dx_setuio( ) function.

The application can override the standard I/O functions on a file-by-file basis by setting the IO_UIO flag in the io_type field of the DX_IOTT structure (see the chapter on Data Structures for details).

NOTE:

The IO_UIO flag must be ORed with the IO_DEV flag for this feature to function properly.

When using the dx_setuio( ) function to record, a user-defined write( ) function must be provided. User-defined read( ) and lseek( ) functions are optional.

When using the dx_setuio( ) function to play, a user-defined read( ) function must be provided. User-defined write( ) and lseek( ) functions are optional.

Cautions

In order for the application to work properly, the user-provided functions MUST conform to standard I/O function semantics.

Example

#include <stdio.h>  
#include <srllib.h>  
#include <dxxxlib.h>  
#include <windows.h>  
#include "VOXLIB.H"     /* Dialogic voice library header file */  
int cd;                 /* channel descriptor */  
DX_UIO myio;            /* user definable I/O structure */  
/*  
 * User defined I/O functions  
 */  
int my_read9(fd,ptr,cnt)  
int fd;  
char * ptr;  
unsigned cnt;  
{  
   printf("My read\n");  
   return(read(fd,ptr,cnt));  
}  
/*  
 * my write function  
 */  
int my_write(fd,ptr,cnt)  
int fd;  
char * ptr;  
unsigned cnt;  
{  
printf("My write \n");  
   return(write(fd,ptr,cnt));  
}  
/*  
 * my seek function  
 */  
long my_seek(fd,offset,whence)  
int fd;  
long offset;  
int whence;  
{  
   printf("My seek\n");  
   return(lseek(fd,offset,whence));  
}  
void main(argc,argv)  
int argc;  
char *argv[];  
{  
   .  
   . /* Other initialization */  
   .  
   DX_UIO uioblk;  
/* Initialize the UIO structure */  
uioblk.u_read=my_read;  
uioblk.u_write=my_write;  
uioblk.u_seek=my_seek;  
/* Install my I/O routines */  
dx_setuio(uioblk);  
vodat_fd = dx_fileopen("JUNK.VOX",O_RDWR|O_BINARY);  
/*This block uses standard I/O functions */  
iott->io_type = IO_DEV|IO_CONT  
iott->io_fhandle = vodat_fd;  
iott->io_offset = 0;  
iott->io_length = 20000;  
/*This block uses my I/O functions */  
iottp++;  
iottp->io_type = IO_DEV|IO_UIO|IO_CONT  
iottp->io_fhandle = vodat_fd;  
iott->io_offset = 20001;  
iott->io_length = 20000;  
/*This block uses standard I/O functions */  
iottp++  
iott->io_type = IO_DEV|IO_CONT  
iott->io_fhandle = vodat_fd;  
iott->io_offset = 20002;  
iott->io_length = 20000;  
/*This block uses my I/O functions */  
iott->io_type = IO_DEV|IO_UIO|IO_EOT  
iott->io_fhandle = vodat_fd;  
iott->io_offset = 10003;  
iott->io_length = 20000;  
devhandle = dx_open("dxxxB1C1", NULL);  
dx_sethook(devhandle, DX-ONHOOK,EV_SYNC)  
dx_wtring(devhandle,1,DX_OFFHOOK,EV_SYNC);  
dx_clrdigbuf;  
   if(dx_rec(devhandle,iott,(DX_TPT*)NULL,RM_TONE|EV_SYNC) == -1) {  
  perror("");  
  exit(1);  
}  
dx_clrdigbuf(devhandle);  
   if(dx_play(devhandle,iott,(DX_TPT*)EV_SYNC) == -1 {  
   perror("");  
   exit(1);  
   }  
   dx_close(devhandle);

Errors

None.

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