amiga-bootcamp/07_dos/error_handling.md

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Error Handling — IoErr, Fault, PrintFault, Error Codes

Overview

Every DOS function that can fail sets an error code retrievable via IoErr(). The error code is stored in pr_Result2 of the calling process.

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API

LVO	Function	Description
−132	IoErr()	Return last error code
−138	SetIoErr(code)	Set error code manually
−468	Fault(code, header, buf, len)	Format error message into buffer
−474	PrintFault(code, header)	Print error message to stderr

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Complete Error Code Table

Code	Constant	Meaning
103	ERROR_NO_FREE_STORE	Out of memory
104	ERROR_TASK_TABLE_FULL	Process table full
114	ERROR_BAD_TEMPLATE	Bad template for ReadArgs
115	ERROR_BAD_NUMBER	Bad number in argument
116	ERROR_REQUIRED_ARG_MISSING	Required argument missing
117	ERROR_KEY_NEEDS_ARG	Keyword requires an argument
118	ERROR_TOO_MANY_ARGS	Too many arguments
119	ERROR_UNMATCHED_QUOTES	Unmatched quotes
120	ERROR_LINE_TOO_LONG	Argument line too long
121	ERROR_FILE_NOT_OBJECT	Not a valid executable
122	ERROR_INVALID_RESIDENT_LIBRARY	Invalid resident library
202	ERROR_OBJECT_IN_USE	Object is in use
203	ERROR_OBJECT_EXISTS	Object already exists
204	ERROR_DIR_NOT_FOUND	Directory not found
205	ERROR_OBJECT_NOT_FOUND	Object not found
206	ERROR_BAD_STREAM_NAME	Invalid stream name
207	ERROR_OBJECT_TOO_LARGE	Object too large
209	ERROR_ACTION_NOT_KNOWN	Action not known (by handler)
210	ERROR_INVALID_COMPONENT_NAME	Invalid filename component
211	ERROR_INVALID_LOCK	Invalid lock
212	ERROR_OBJECT_WRONG_TYPE	Object wrong type
213	ERROR_DISK_NOT_VALIDATED	Disk not validated
214	ERROR_DISK_WRITE_PROTECTED	Disk is write-protected
215	ERROR_RENAME_ACROSS_DEVICES	Rename across devices
216	ERROR_DIRECTORY_NOT_EMPTY	Directory not empty
217	ERROR_TOO_MANY_LEVELS	Too many directory levels
218	ERROR_DEVICE_NOT_MOUNTED	Device not mounted
219	ERROR_SEEK_ERROR	Seek error
220	ERROR_COMMENT_TOO_BIG	Comment too big
221	ERROR_DISK_FULL	Disk full
222	ERROR_DELETE_PROTECTED	Delete protected
223	ERROR_WRITE_PROTECTED	Write protected
224	ERROR_READ_PROTECTED	Read protected
225	ERROR_NOT_A_DOS_DISK	Not a DOS disk
226	ERROR_NO_DISK	No disk in drive
232	ERROR_NO_MORE_ENTRIES	No more directory entries
233	ERROR_IS_SOFT_LINK	Object is a soft link
234	ERROR_OBJECT_LINKED	Object is hard-linked
235	ERROR_BAD_HUNK	Bad hunk in executable
236	ERROR_NOT_IMPLEMENTED	Function not implemented
240	ERROR_RECORD_NOT_LOCKED	Record not locked
241	ERROR_LOCK_COLLISION	Record lock collision
242	ERROR_LOCK_TIMEOUT	Record lock timeout
243	ERROR_UNLOCK_ERROR	Unlock error

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Usage Pattern

BPTR fh = Open("nonexistent", MODE_OLDFILE);
if (!fh) {
    LONG err = IoErr();
    PrintFault(err, "myapp");
    /* prints: "myapp: Object not found" */
}

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References

• NDK39: dos/dos.h, dos/dosasl.h
• ADCD 2.1: IoErr, Fault, PrintFault