Editing Exit status (section)

===DOS===
In DOS terminology, an '''errorlevel''' is an [[integer]] exit [[code]] returned by an [[executable|executable program]] or [[subroutine]]. Errorlevels typically range from 0 to 255.<ref name="Paul_1997_BATTIPS"/><ref name="FD_2003_Errorlevel"/><ref name="Paul_1997_NWDOSTIP"/><ref name="Allen_2005"/> In [[DOS]] there are only 256 error codes available, but [[DR&nbsp;DOS 6.0]] and higher support 16-bit error codes at least in [[CONFIG.SYS]].<ref name="Paul_1997_NWDOSTIP"/> With [[4DOS]] and DR-DOS [[COMMAND.COM]], exit codes (in batchjobs) can be set by [[EXIT (DOS command)|EXIT ''n'']]<!-- MS-DOS/PC DOS COMMAND.COM does not support the optional parameter, just EXIT without any arguments --><ref name="Paul_1997_NWDOSTIP"/> and (in CONFIG.SYS) through [[ERROR (CONFIG.SYS directive)|ERROR=''n'']]<!-- and a number of other more specialized directives -->.<ref name="Paul_1997_NWDOSTIP"/>

Exit statuses are often captured by [[batch file|batch programs]] through [[IF ERRORLEVEL (DOS command)|IF ERRORLEVEL]] commands.<ref name="Paul_1997_BATTIPS"/><ref name="Paul_1997_NWDOSTIP"/> [[Multiuser DOS]] supports a reserved <!-- true -->[[environment variable]] [[%ERRORLVL%]] which gets automatically updated on return from applications. COMMAND.COM under [[DR-DOS 7.02]] and higher supports a similar [[pseudo-environment variable]] %ERRORLVL% as well as [[%ERRORLEVEL%]].<!-- MS-DOS and PC DOS do not, only Windows does! --> In CONFIG.SYS, DR&nbsp;DOS 6.0 and higher supports [[ONERROR (CONFIG.SYS directive)|ONERROR]] to test the load status and return code of device drivers and the exit code of programs.<ref name="Paul_1997_NWDOSTIP"/>