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.

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

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

Usage Pattern

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

References

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