What is the most appropriate way to batch test ERRORLEVEL?

Question

I’ve seen several forms of testing ERRORLEVEL in batch scripts. Some of them are dangerous and others are wrong, but sometimes go unnoticed. Below are some examples I know:

Dangerous: the test works as "greater than or equal to 1", ignoring negative returns (used in programs in "C"). Here you don’t have to worry about limiting block expansion.

if errorlevel 1 (
   echo Comando executado com problema
)

Wrong: the test works as "greater than or equal to 0", indicating true for return with or without error

if errorlevel 0 (
   echo Comando executado com sucesso
)

Doubtful: Tests the result of executing a command or batch successfully and error, respectively. This form is interesting, but there is the question of limiting expansion in IF/FOR blocks, etc.

if "%ERRORLEVEL%"=="0" (
   echo Comando executado com sucesso
)

if not "%ERRORLEVEL%"=="0" (
   echo Comando executado com problema
)

• Which of these forms is more suitable?
• There is an even better unquoted form?

Answer 1

Probably the last option because of the readability and enable dealing with negative returns.

IF %ERRORLEVEL% EQU 0 ( 
  echo OK
) ELSE ( 
  echo ERRO
)

Another alternative with conditional:

IF %ERRORLEVEL% EQU 0 echo OK || echo ERRO

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_{Bonus: To specify the return of a subroutine, use exit /b [n], where n is the return code.}