Common Parameters

Flags Parameter

The flags parameter is a bit representation, 32 bits long, of various options. Normally an option is invoked if the appropriate bit is on (that is, set equal to 1). Borrowing Pascal-type syntax, we shall use flags [0] to refer to the high order bit in the parameter, flags [31] to refer to the low order bit, and a similar designation to refer to each of the bits in between. Bits which are not defined for a given intrinsic must be off (zero).

Opt Parameter

The opt parameter, which denotes various options, contains an integer code for each option along with associated information. It is not necessary to know the internal structure of this parameter in order to use it. Several opt parameter manipulation intrinsics have been provided to enable you to add option information without concerning yourself with the parameter's structure. However, a knowledge of the structure of the opt parameter can help you to determine an appropriate size for the array.

The opt parameter must be defined as a byte array or as a record structured in the manner described below. If your program is written in a language which supports dynamically allocated arrays, the OPTOVERHEAD intrinsic may be used to determine the size of the array.

The opt parameter consists of these fields as shown in Figure 3-1 “OPT Parameter Structure”.

If the parameter is declared as a simple byte array, it must be large enough to contain 4 bytes for the first two fixed-length fields, 8 bytes for each option entry, plus the actual data. That is:

     4  +  8 * numentries  +  datalength

	NOTE: Use of certain opt parameter options may result in the loss of portability between different Hewlett-Packard systems.

Figure 3-1 OPT Parameter Structure

Figure 3-2 “Option Entry Structure.” shows the structure of an option entry.

Figure 3-2 Option Entry Structure.

Data Parameter

The data parameter is defined as a byte array. It can be in one of two formats: either holding the actual data or in a vectored format. In the case of vectored data, the data parameter does not contain actual data but rather the addresses from or to which the data will be gathered or distributed.

The addresses of the data are represented by data location descriptors. For all intrinsics supporting vectored data, a maximum of two data location descriptors is permitted.

For vectored data, the parameter must be a record structured as described below. The format of a compatibility mode data location descriptor is different than a native mode data location descriptor as shown in Figure 3-3 “Data Location Descriptor — Vectored Data”.

Combining a compatibility mode vector with a native mode vector in the same NetIPC call is not supported.

Figure 3-3 Data Location Descriptor — Vectored Data

     nm_address:= globalanyptr(addr(data));

Result Parameter

If a NetIPC (or Remote Process Management) intrinsic call is successful, the result parameter returns a value of zero. Otherwise the value returned represents a NetIPC error code (SOCKERR). NetIPC error messages are listed in Appendix A “IPC Interpreter (IPCINT)”of this manual. You can also obtain the corresponding error message by calling IPCERRMSG.

	NOTE: When nowait I/O is used, the result parameter is not updated upon completion of an intrinsic. Therefore, the value of result only indicates whether the call was successfully initiated. To determine if the call completed successfully, you can use the IPCCHECK intrinsic immediately afterward.