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Inside Macintosh: Devices /

Chapter 2 - Slot Manager / Slot Manager Reference

Slot Manager Routines / Getting Information From sResources

SFindStruct

You can use the SFindStruct function to obtain a pointer to any data structure pointed to by the offset field of an sResource entry. You might want to use this function, for example, when the data structure type is defined by the card designer.

FUNCTION SFindStruct (spBlkPtr: SpBlockPtr): OSErr;

spBlkPtr

A pointer to a Slot Manager parameter block.

<-->	spsPointer	Ptr	On input: a pointer to an sResource. On output: a pointer to a data structure.
-->	spID	SignedByte	The ID of the sResource entry.
X	spByteLanes	SignedByte

DESCRIPTION

You provide a pointer to the sResource in the spsPointer field, and the ID of the entry in the spID field. The SFindStruct function returns a pointer to the data structure in the spResult field.

SPECIAL CONSIDERATIONS

This function may alter the value of the spByteLanes field of the parameter block. Your application should not depend on the value returned in this field.

ASSEMBLY-LANGUAGE INFORMATION

The trap macro and routine selector for the SFindStruct function are

Trap macro	Selector
_SlotManager	$0006

You must set up register D0 with the routine selector and register A0 with the address of the Slot Manager parameter block. When _SlotManager returns, register D0 contains the result code.

Registers on entry
A0	Address of the parameter block
D0	$0006

Registers on exit
D0	Result code

RESULT CODES

noErr	0	No error
smNoMoresRsrcs	-344	Requested sResource not found

SEE ALSO

For information about obtaining a copy of a data structure pointed to by the offset field of an sResource entry, rather than a pointer to the data structure, see the next section, which describes the SReadStruct function.