- 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