Странное поведение CHOICE (batch file)

← →
Lamer@fools.ua © (2012-02-14 22:41) [0]

1.cmd:
@echo off

if 1 equ 1 (
choice /c 12 /m "Press 1 to continue; 2 to cancel" /t 30 /d 2
echo A: %ERRORLEVEL%
if %ERRORLEVEL% neq 1 (
echo * Cancelled.
)
)

2.cmd:
@echo off

REM if 1 equ 1 (
choice /c 12 /m "Press 1 to continue; 2 to cancel" /t 30 /d 2
echo A: %ERRORLEVEL%
if %ERRORLEVEL% neq 1 (
echo * Cancelled.
)
REM )

Win 7 x64
Кто виноват и что делать?

← →
Lamer@fools.ua © (2012-02-14 22:42) [1]

В варианте 1 (со вложенным IF-ом), ERRORLEVEL всегда 0.

← →
Lamer@fools.ua © (2012-02-14 22:45) [2]

Сам спросил. Сам ответил. ERRORLEVEL принимает правильное значение при выходе из IF-а. Всегда приятно поговорить с умным собеседником :)

P.S. Но всё равно кто-то виноват. Надо разобраться как следует и наказать кого попало.

← →
Lamer@fools.ua © (2012-02-14 22:50) [3]

На всякий случай напишу workaround:

if 1 neq 1 goto SKIP_CHOICE choice /c 12 /m "Press 1 to continue; 2 to cancel" /t 30 /d 2 echo A: %ERRORLEVEL% if %ERRORLEVEL% neq 1 ( echo * Cancelled. ) :SKIP_CHOICE

Случайно нашел описание этой проблемы в справке по команде SET:

Finally, support for delayed environment variable expansion has been added. This support is always disabled by default, but may be enabled/disabled via the /V command line switch to CMD.EXE. See CMD /? Delayed environment variable expansion is useful for getting around the limitations of the current expansion which happens when a line of text is read, not when it is executed. The following example demonstrates the problem with immediate variable expansion: set VAR=before if "%VAR%" == "before" ( set VAR=after if "%VAR%" == "after" @echo If you see this, it worked ) would never display the message, since the %VAR% in BOTH IF statements is substituted when the first IF statement is read, since it logically includes the body of the IF, which is a compound statement. So the IF inside the compound statement is really comparing "before" with "after" which will never be equal. Similarly, the following example will not work as expected: set LIST= for %i in (*) do set LIST=%LIST% %i echo %LIST% in that it will NOT build up a list of files in the current directory, but instead will just set the LIST variable to the last file found. Again, this is because the %LIST% is expanded just once when the FOR statement is read, and at that time the LIST variable is empty. So the actual FOR loop we are executing is: for %i in (*) do set LIST= %i which just keeps setting LIST to the last file found. Delayed environment variable expansion allows you to use a different character (the exclamation mark) to expand environment variables at execution time. If delayed variable expansion is enabled, the above examples could be written as follows to work as intended: set VAR=before if "%VAR%" == "before" ( set VAR=after if "!VAR!" == "after" @echo If you see this, it worked ) set LIST= for %i in (*) do set LIST=!LIST! %i echo %LIST%

Странное поведение CHOICE (batch file) Найти похожие ветки