- added GetErrorLevel and SetErrorLevl

- fixed some inconsistencies in the error levels the installer/uninstaller set


git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@3668 212acab6-be3b-0410-9dea-997c60f758d6

Docs/src/misc.but

@@ -1,5 +1,11 @@
 \S1{miscinst} Miscellaneous Instructions
 
+\S2{geterrorlevel} GetErrorLevel
+
+\c user_var(error level output)
+
+Returns the last error level set by \R{seterrorlevel}{SetErrorLevel} or -1 if it was never used.
+
 \S2{getinstdirerror} GetInstDirError
 
 \c user_var(error output)
@@ -16,6 +22,12 @@ Use in the leave function of a directory page. Reads the flag set if '\R{adirver
 
 Initializes the plugins dir (\R{varconstant}{$PLUGINSDIR}) if not already initialized.
 
+\S2{seterrorlevel} SetErrorLevel
+
+\c error_level
+
+Sets the error level of the installer or uninstaller to \e{error_level}. See \R{errorlevels}{Error Levels} for more information.
+
 \S2{setshellvarcontext} SetShellVarContext
 
 \c \\<b\\>current\\</b\\>|all

Docs/src/usefulinfos.but

@@ -20,21 +20,15 @@ When building with precompiled exehead .h files, you should set the USE_PRECOMPI
 
 Like other applications installers made by NSIS return error levels as a result of their execution. Checking the error level can be useful if you call an NSIS installer from another application or installer.
 
-Normal installers:
-
 \b 0 - Normal execution (no error)
 
-\b 1 - Installation aborted by user
+\b 1 - Installation aborted by user (cancel button)
 
 \b 2 - Installation aborted by script
 
-Silent installers:
+As of NSIS 2.01, you can set the error level to other values using \R{seterrorlevel}{SetErrorLevel}.
 
-\b 0 - Normal execution (no error)
-
-\b 1 - Installation aborted by user
-
-\b 1 - Installation aborted by script
+All of the above information applies both to installers and uninstallers.
 
 \H{useful_add_uninst_infos}Add uninstall information to Add/Remove Programs