EMI Compiler Directives

All EMI compiler directives start with character '/'. Compiler directives supported by EMI by now are

• /include Directive
• Conditional Compilation Directives

/include Directive

Directive /include can be used to include other source units from a specific source unit. Format of directive /include is:

/include ["]path-name["];

description

• path-name can be absolute path names or relative path names of IFS or database file system.
• When path-name contains white spaces, use double or single quotes to quote the path-name.
• Example of using directive /include

     /* /qsys.lib source path */
     /include /qsys.lib/srclib.lib/misrc.file/world.emi;
  
     /* stream file */
     /include /home/ljl/mi-src/world.emi;
  
     /* relative path name */
     /include ../inc/world.emi;
  
     /* path name including white spaces */
     /include '/home/ljl/mi src/one two three . emi ';
  

Conditional Compilation Directives

Directive /define, /undef, /ifdef, /ifndef, /endif, /else are designed for conditional compilation. The following table shows the formats of EMI's conditional compilation directives.

Directive Name	Format	Description
/define	/define macro-name	define a macro
/undef	/undef macro-name	undefine a macro
/ifdef	/ifdef macro-name	test if a macro has been defined
/ifndef	/ifndef	test if a macro has NOT been defined
/endif	/endif	end the most recent /ifdef or /ifndef group
/else	/else	as its literal meanings

Example of Using EMI Conditional Compilation Directives

In the following example, source unit oct1.emi includes another source unit oct-inc.emi. We can see two typical usage of conditional compilation directives here.

• oct-inc.emi uses macro __oct_inc__ to proctect itself from being included twice.

• macro __chinese__ is used to determine the value of constant oct-greeting depending on whether or not macro __chinese__ has been defined when the compiler comes across the included source unit, oct-inc.emi.

/* *
 * @file oct1.emi
 *
 * includes oct-inc.emi
 */

/define __chinese__         ;  /* defines MACRO __chinese__ */
        
entry * ext                     ;

dcl dd buf char(40) auto        ;
dcl dd hex char(2) auto         ;
dcl dd str char(4) auto init('19EF') ;

        cvtch hex, str          ;

        cpyblap oct-err,
          oct-greeting,
          " "                   ;
        triml oct-len, oct-err, ' ' ;
        %sendmsg(oct-err, oct-len)  ;

brk 'RRR'                       ;
        rtx *                   ;

/include oct-inc.emi            ;
/include oct-inc.emi            ; /* includes oct-inc.emi twice */

pend                            ;

/* *
 * @file oct-inc.emi
 */

/ifndef __oct_inc__             ;
/define __oct_inc__             ;

dcl dd oct-err char(32) auto    ;
dcl dd oct-len bin(2) auto      ;

/ifdef __chinese__          ;
dcl con oct-greeting char(16)
        init(x"0E56755655569C55C64DC254CA0F") ;
/else                           ;
dcl con oct-greeting char(32)
        init("Soe said he's a kind man.") ;
/endif                          ;

/endif                          ;

/* eof - oct-inc.emi */

Run program OCT1

> call oct1    
  苏说他是好人