---
name: "DlpRPC"
section: "3"
platform: "linux"
package: "coldsync"
version: "3.0+pre3-3"
release: "Debian 4.0 (Etch)"
platforms: ["linux"]
url: "https://new.carta.tech/DlpRPC"
---

# DlpRPC(3)

make remote procedure call on PalmOS device

## NAME

**DlpRPC** – make remote procedure call on PalmOS device

## LIBRARY

*libpconn*

## SYNOPSIS

**#include \<palm.h\>**

**#include \<pconn/pconn.h\>**

*int*\

**DlpRPC**(*PConnection \*pconn*, *uword trap*, *udword \*D0*, *udword \*A0*, *int argc*, *struct DLPRPC\_param \*argv*);

## DESCRIPTION

**DlpRPC** makes a remote procedure call on the Palm. That is, this function requests that the Palm execute a particular system function with certain arguments. **DlpRPC** then returns the (integer) return value of the system call, and fills in any by-reference arguments.

*trap* specifies the trap number of the system call to make.

*D0* and *A0* specify the initial values of the D0 and A0 registers. After the remote procedure call, these arguments are filled in with the new values of D0 and A0. D0 is typically used for the return value.

*argc* specifies the number of arguments in *argv*.

*argv* is an array of function arguments to pass. The elements of *argv* are in reverse order from the function declaration. That is, if a system call is declared as **SysFunc**(*a*, *b*, *c*), then *argv\[0\]* will contain *a*, *argv\[1\]* will contain *b*, and *argv\[2\]* will contain *c* ( *argc* should, of course, be set to 3). The *DLPRPC\_param* structure is defined as

```
struct DLPRPC_param {
	Bool byref;
	ubyte size;
	char type;
	union {
		ubyte bool_v;
		ubyte byte_v;
		uword word_v;
		udword dword_v;
		void *raw_v;
	} data;
};
```

where *byref* is true if this argument is passed by reference, *size* specifies the size of the argument (this is only required for raw arguments), *type* specifies the argument type (see the RPCP\_\* constants in *\<pconn/dlp\_rpc.h\>* ), and *data* contains the actual argument data.

This should be relatively straightforward for boolean and integer arguments. Raw arguments deal with byte strings of arbitrary length. The length of the data is specified with *argv\[i\].size*. *argv\[i\].data.raw\_v* must point to a buffer of sufficient size to hold the returned data. **DlpRPC** reads from and writes to this pointer, but does not allocate or free it.

## RETURN VALUE

**DlpRPC** returns 0 if successful, or a negative value otherwise. Note that it is quite possible for **DlpRPC** to succeed, and for the remote procedure call to fail. For example, if **DlpRPC** is used to read a nonexistent memory range, **DlpRPC** will return 0, but *D0* (which is typically used for the system call's return value) will be nonzero.

## SEE ALSO

[libpconn(3)](/libpconn/3.md), [RDLP\_ROMToken(3)](/RDLP_ROMToken/3.md), [RDLP\_MemMove(3)](/RDLP_MemMove/3.md).