ERRORLEVEL is a number value which is set by programs and may be tested
within a DOS Batch file.
The following batch statements are examples of testing ERRORLEVEL:
CONFIRM Do you really want to exit? (Esc to cancel)
IF ERRORLEVEL 1 GOTO RESUME
GOTO END
The CONFIRM program above displays a message on the screen and
waits for a keystroke. If the keystroke is the Esc key, ERRORLEVEL is
set to 1, any other key sets ERRORLEVEL to 0. The IF ERRORLEVEL
statement above branches to the RESUME label if the user presses Esc,
otherwise the GOTO END statement is executed branching to the END
label.
The IF ERRORLEVEL statement does not check for equality, but is really a
"greater than or equal to" comparison. For example, IF ERRORLEVEL 5
really means: "if ERRORLEVEL is 5 or higher".
If you need to check for a number of ERRORLEVEL possibilities, use a number
of IF ERRORLEVEL statements testing from high to low, like this:
IF ERRORLEVEL 10 GOTO LABEL10
IF ERRORLEVEL 9 GOTO LABEL9
IF ERRORLEVEL 8 GOTO LABEL8
IF ERRORLEVEL 7 GOTO LABEL7
IF ERRORLEVEL 6 GOTO LABEL6
IF ERRORLEVEL 5 GOTO LABEL5
IF ERRORLEVEL 4 GOTO LABEL4
IF ERRORLEVEL 3 GOTO LABEL3
IF ERRORLEVEL 2 GOTO LABEL2
IF ERRORLEVEL 1 GOTO LABEL1
GOTO LABEL0
Another way to test ERRORLEVEL is to preceed it with NOT to test for
"less than", like this:
IF NOT ERRORLEVEL 10 GOTO Less_than_10
To test for a single ERRORLEVEL or a range, do this:
IF ERRORLEVEL 10 IF NOT ERRORLEVEL 11 GOTO Err_10
IF ERRORLEVEL 5 IF NOT ERRORLEVEL 10 GOTO Err_5_to_9
To set the ERRORLEVEL from a batch file:
EXIT /B 1
(Note: parameters for the EXIT command are supported in Windows 2000
and up. For older versions of Windows and DOS, or to set ERRORLEVEL without
exiting, use SETERR)
The command interpreter (Command Prompt) sets ERRORLEVEL 9009 when a batch
attempts to execute a program that is not found. The line below may be
added to a batch file immediately after the line that executes a program
so that the batch will branch to the ProgNotFound label and exit gracefully
instead of blindly continue running:
MyProg1.exe
IF ERRORLEVEL 9009 IF NOT ERRORLEVEL 9010 GOTO ProgNotFound
.
.
.
:ProgNotFound
ECHO One or more programs required by this routine were not found. These
ECHO programs are required for this routine:
ECHO MyProg1.exe
ECHO MyProg2.exe
The command interpreter (Command Prompt) sets ERRORLEVEL 1 when a batch
attempts to CALL another batch and the batch is not found. Unfortunately,
if ERRORLEVEL was not zero before a CALL and the CALL to another batch
is found, the ERRORLEVEL is NOT set to 0. So, checking IF ERRORLEVEL 1
after a CALL is true if the batch file was not found or if a previously
untrapped ERRORLEVEL was set. The SETERR utility may be used
to set ERRORLEVEL in batches, or reset it to 0, without exiting.
The command interpreter (Command Prompt) sets ERRORLEVEL 9059 when START
is used to start a program or a batch and it is not found.
The internal command DEL (or ERASE) do not set an errorlevel if the file
is not found, but sets ERRORLEVEL 18 if an "Access is denied" error occurs.
The internal command CD (or CHDIR) sets ERRORLEVEL 1 if path not found.
The internal command MD (or MKDIR) sets ERRORLEVEL 1 if file already exists.
The GOTO batch command sets ERRORLEVEL 1 if label is not found. While it is
not difficult to determine that all of the labels referenced by GOTO in your
batch files exist, checking the ERRORLEVEL after a GOTO would work well in
a situation where you are using GOTO with a label name that is derived from
a batch parameter or an environment variable. For example, both of these
GOTO statements are valid and checking the ERRORLEVEL after these indirect
GOTO references will allow the batch to self diagnose an invalid label:
Incode Systems, Inc.