[Info-vax] VMS databases

[Arne Vajhøj]

On 11/18/2023 7:04 PM, Craig A. Berry wrote:
> On a semi-related note, I once wrote wrappers around some of the socket
> routines so I could call them from BASIC.  recv looked like this:
> 
> #define BASIC_True -1
> #define BASIC_False 0
> 
> int
> mytcp_recv( int *sockfd,
>               struct dsc$descriptor_d *msg_dsc,
>               int *bytes_read,
>               struct dsc$descriptor_d *errmsg_dsc ) {
> 
>      *bytes_read = recv( *sockfd,
>                          msg_dsc->dsc$a_pointer,
>                          msg_dsc->dsc$w_length,
>                          0 );
> 
>      if ( *bytes_read < 0 ) {
>          /* other error reporting */
>          return(BASIC_False);
>      }
> 
>      return(BASIC_True);
> }
> 
> Call it from BASIC like so:
> 
>    EXTERNAL LONG FUNCTION MYTCP_RECV(  LONG BY REF, STRING BY DESC, LONG 
> BY REF, STRING BY DESC )
>    SOCKET_SUCCESS = MYTCP_RECV( SOCKET, MESSAGE, DATA_LENGTH, ERRMSG )
> 
> I think it took me a bit to wise up to the fact that BASIC's descriptors
> are dynamic and needed the dsc$descriptor_d declarations.

I know that.

For moving data into the Basic string I use:

static void bstr(char *buf, int buflen, struct dsc$descriptor_d *d)
{
     lib$sget1_dd(&buflen, d);
     d->dsc$b_dtype = DSC$K_DTYPE_T;
     memcpy(d->dsc$a_pointer, buf, buflen);
}

Some code I had on the shelf. Not sure where I got it from.

Arne