* See $LK,"Scoping and Linkage",A="FI:::/Doc/ScopingLinkage.DD"$ for details on $FG,2$extern$FG$, $FG,2$import$FG$, $FG,2$_extern$FG$, $FG,2$_import$FG$, etc.
* Built-in types include $FG,2$I0,I8,I16,I32,I64$FG$ for signed 0-8 byte ints and $FG,2$U0,U8,U16,U32,U64$FG$ for unsigned 0-8 byte ints and $FG,2$F64$FG$ for 8 byte floats.
* A char const all alone is sent to $LK,"PutChars",A="MN:PutChars"$(). A string with or without args is sent to $LK,"Print",A="MN:Print"$(). An empty string literal signals a variable format_str follows.
* Type casting is postfix. To typecast int or F64, use $LK,"ToI64",A="MN:ToI64"$(), $LK,"ToBool",A="MN:ToBool"$() or $LK,"ToF64",A="MN:ToF64"$(). (ZenithOS follows normal C float<-->int conversion, but sometimes you want to override. These functions are better than multiplying by "1.0" to convert to float.)
* There are no bit fields, but there are $LK,"bit access",A="HI:Bit"$ routines and you can access bytes or words within any int. See $LK,"I64 declaration",A="MN:I64"$. A class can be accessed as a whole are subints, if you put a type in front of the $FG,2$class$FG$ declaration.
* Variable arg count functions ($FG,2$...$FG$) can access their args with built-in variables similar to '$FG,2$this$FG$' in C++. They are '$FG,2$I64 argc$FG$' and '$FG,2$I64 argv[]$FG$'.
* Switch statements can be nestled with a single switch expression! This is known as a "sub_switch" statement. $FG,2$start$FG$/$FG,2$end$FG$ are used to group cases. Don't goto out of, throw an exception out of, or return out of the $FG,2$start$FG$ front porch area. See $LK,"::/Demo/SubSwitch.CC"$.
//Only use $LK,"REGG_LOCAL_VARS",A="MN:REGG_LOCAL_VARS"$ or $LK,"REGG_LOCAL_NON_PTR_VARS",A="MN:REGG_LOCAL_NON_PTR_VARS"$ for reg vars or else clobbered.
* $FG,2$interrupt$FG$, $FG,2$haserrcode$FG$, $FG,2$public$FG$, $FG,2$argpop$FG$ or $FG,2$noargpop$FG$ are function flags. See $LK,"IRQKbd",A="MN:IRQKbd"$().
* A single quote can encompass multiple characters. $FG,2$'ABC'$FG$ is equ to $FG,2$0x434241$FG$. $LK,"PutChars",A="MN:PutChars"$() takes multiple characters.
* With the $FG,2$#exe{}$FG$ feature in your src code, you can place programs that insert text into the stream of code being compiled. See $LK,"#exe {}",A="FF:::/Kernel/KMain.CC,#exe {"$ for an example where the date/time and compile-time prompting for configuration data is placed into a program. $LK,"StreamPrint",A="MN:StreamPrint"$() places text into a src program stream following the conclusion of the $FG,2$#exe{}$FG$ blk.
* "$FG,2$$$$FG$" is an escape character. Two dollar signs signify an ordinary $$. See $LK,"DolDoc",A="FI:::/Doc/DolDocOverview.DD"$. In $FG,2$asm$FG$ or $LK,"CosmiC",A="FI:::/Doc/CosmiC.DD"$ code, it also refers to the inst's address or the offset in a $FG,2$class$FG$ definition.
* $FG,2$union$FG$ is more like a class, so you don't reference it with a $FG,2$union$FG$ label after you define it. Some common unions are declared in $LK,"KernelA.HH",A="MN:U16"$ for 1,2,4 and 8 byte objects. If you place a type in front of a union declaration, that is the type when used by itself. See $LK,"::/Demo/SubIntAccess.CC"$.
* $FG,2$class$FG$ member vars can have meta data. $FG,2$format$FG$ and $FG,2$data$FG$ are two meta data types now used. All compiler structures are saved and you can access the compiler's info about classes and vars. See $LK,"::/Demo/ClassMeta.CC"$ and $LK,"DocForm",A="MN:DocForm"$().
* There is a keyword $FG,2$lastclass$FG$ you use as a default arg. It is set to the class name of the prev arg. See $LK,"::/Demo/LastClass.CC"$, $LK,"ClassRep",A="MN:ClassRep"$(), $LK,"DocForm",A="MN:DocForm"$() and $LK,"::/Demo/Disk/BlkDevRep.CC"$.
* See $LK,"::/Demo/Exceptions.CC"$. $FG,2$try{} catch{}$FG$ and $FG,2$throw$FG$ are different from C++. $FG,2$throw$FG$ is a function with an 8-byte or less char arg. The char string passed in $FG,2$throw()$FG$ can be accessed from within a $FG,2$catch{}$FG$ using the $FG,2$Fs->except_ch$FG$. Within a $FG,2$catch {}$FG$ blk, set the var $FG,2$Fs->catch_except$FG$ to $FG,2$TRUE$FG$ if you want to terminate the search for a handler. Use $LK,"PutExcept",A="MN:PutExcept"$() as a handler, if you like.
* A function is available similar to $FG,2$sizeof$FG$ which provides the offset of a member of a class. It's called $FG,2$offset$FG$. You place the class name and member inside as in $FG,2$offset(classname.membername)$FG$. It has nothing to do with 16-bit code. Both $FG,2$sizeof$FG$ and $FG,2$offset$FG$ only accept one level of member vars. That is, you can't do $FG,2$sizeof(classname.membername.submembername)$FG$.$FG$
* $FG,2$lock{}$FG$ can be used to apply asm $FG,2$LOCK$FG$ prefixes to code for safe multicore read-modify-write accesses. The code bracked with have $FG,2$LOCK$FG$ asm prefix's applied to relevant insts within. It's a little shoddy. See $LK,"::/Demo/MultiCore/Lock.CC"$.
* There is a function called $LK,"MSize",A="MN:MSize"$() which gives the size of an object alloced off the heap. For larger size allocations, the system rounds-up to a power of two, so $FG,2$MSize()$FG$ lets you know the real size and you can take full advantage of it.
* You CAN $LK,"Free",A="MN:Free"$() a $FG,2$NULL$FG$ ptr. Useful variants of $LK,"MAlloc",A="MN:MAlloc"$() can be found $LK,"Here",A="MN:CAlloc"$. Each task has a heap and you can $FG,2$MAlloc$FG$ and $FG,2$Free$FG$ off-of other task's heaps, or make an independent heap with $LK,"HeapCtrlInit",A="MN:HeapCtrlInit"$(). See $LK,"HeapLog",A="MN:HeapLog"$() for an example.
* The stack does not grow because virtual mem is not used. I recommend allocating large local vars from the heap. You can change $LK,"MEM_DEFAULT_STACK",A="MN:MEM_DEFAULT_STACK"$ and recompile $FG,2$Kernel$FG$ or request more when doing a $LK,"Spawn",A="MN:Spawn"$(). You can use $LK,"CallStackGrow",A="MN:CallStackGrow"$(), but it's odd. See $LK,"::/Demo/StackGrow.CC"$.
