#command | #translate :

Specify a user-defined command or translation directive

#command <matchPattern> => <resultPattern>
#translate <matchPattern> => <resultPattern>

#define :

Define a manifest constant or pseudofunction

#define <idConstant> [<resultText>]
#define <idFunction>([<arg list>]) [<exp>]

#error :

Generate a compiler error and display a message

#error [<messageText>]

#ifdef :

Compile a section of code if an identifier is defined

#ifdef <identifier>
    <statements>...
[#else]
    <statements>...
#endif

#ifndef :

Compile a section of code if an identifier is undefined

#ifndef <identifier>
    <statements>...
[#else]
    <statements>...
#endif

#include :

Include a file into the current source file

#include "<otherSourceFileSpec>"

#stdout :

Send literal text to the standard output device

#stdout [<messageText>]

#undef :

Remove a #define macro definition

#undef <identifier>

#xcommand | #xtranslate :

Specify a user-defined command or translation directive

#xcommand <matchPattern> => <resultPattern>
#xtranslate <matchPattern> => <resultPattern>