I have tried simple PL/1 program to test the parameter passing in PL/1.
I have tested it BYADDR and got the expected results.
When I try with BYVALUE I got the unexpected results.
Below is my code.
Main program:
- MUPLI: PROC OPTIONS(MAIN);
DCL X FIXED BIN(31,0);
DCL Y FIXED BIN(31,0);
DCL SYSPRINT FILE OUTPUT;
PUT SKIP LIST('ENTER IN TO MAIN PGM');
DCL MUSUB ENTRY OPTIONS(BYVALUE);
PUT SKIP LIST('ENTER AFTER MUSUB DCL');
X=2;
Y=3;
CALL MUSUB( (X), (Y) );
PUT SKIP LIST('VALUES OF X Y:',X,Y);
- END MUPLI;
Sub Program:
MUSUB:PROC(A,B) REORDER;
PUT SKIP LIST('BEFORE DCL');
DCL A FIXED BIN(31,0);
DCL B FIXED BIN(31,0);
PUT SKIP LIST('VALUE OF A =:',A);
PUT SKIP LIST('VALUE OF B =:',B);
PUT SKIP LIST('VALUE OF C =:',A+B);
END MUSUB;
My test results:
ENTER IN TO MAIN PGM
ENTER AFTER MUSUB DCL
BEFORE DCL
VALUE OF A =: 1
VALUE OF B =: 304
VALUE OF C =: 305
VALUES OF X Y: 2 3
Here I am expecting values 2 and 3 to be substituted to parameters A and B but value 1 and 304 substituted.
Can anyone have a look in to the prblem and let me know how 1 and 304 substituted to parameters A and B ?
Your expectations were clashed by Your wrong coding ...
the OPTIONS(BYVALUE) is in the wrong place....
or ... at least the two declarations should be the same
when the two declarations are different
the address is considered as data,
or
the data is considered an address
if You play a bit around with the two combinations You might find out which is which
for PROCs in the same source, no need for the DCL ENTRY stuff
here is a complete TESTED and WORKING snippet of the whole shebang
Code:
****** ***************************** Top of Data ******************************
000001 zmf03:
000002 Proc Options(Main);
000003 dcl x1 fixed bin(31) init(101);
000004 dcl y1 fixed bin(31) init(102);
000005 dcl x2 fixed bin(31) init(201);
000006 dcl y2 fixed bin(31) init(202);
000007
000008 put skip list('Main Starting');
000009 put skip list('declared ');
000010 put skip list('x1 =',x1 );
000011 put skip list('y1 =',y1 );
000012 put skip list('x2 =',x2 );
000013 put skip list('y2 =',y2 );
000014
000015 x1=1101;y1=1102;
000016 x2=1201;y2=1202;
000017
000018 put skip list('assigned ');
000019 put skip list('x1 =',x1 );
000020 put skip list('y1 =',y1 );
000021 put skip list('x2 =',x2 );
000022 put skip list('y2 =',y2 );
000023
000024 call sub1(x1, y1);
000025 put skip list('after sub1');
000026 put skip list('x1 =',x1 );
000027 put skip list('y1 =',y1 );
000028
000029 call sub2(x2, y2);
000030 put skip list('after sub2');
000031 put skip list('x2 =',x2 );
000032 put skip list('y2 =',y2 );
000033
000034 put skip list('Main Ending');
000035 End zmf03 ;
000036
000037 sub1:proc(a1,b1);
000038 dcl a1 fixed bin(31) ;
000039 dcl b1 fixed bin(31) ;
000040 put skip list('sub1 Entered');
000041 put skip list('at entry');
000042 put skip list('a1 =',a1 );
000043 put skip list('b1 =',b1 );
000044 a1 = 2101; b1=2102;
000045 put skip list('aft ');
000046 put skip list('a1 =',a1 );
000047 put skip list('b1 =',b1 );
000048 put skip list('sub1 Leaving');
000049 return;
000050 end sub1;
000051 sub2:proc(a2,b2) options(byvalue);
000052 dcl a2 fixed bin(31) ;
000053 dcl b2 fixed bin(31) ;
000054 put skip list('sub2 Entered');
000055 put skip list('at entry');
000056 put skip list('a2 =',a2 );
000057 put skip list('b2 =',b2 );
000058 a2 = 2101; b2=2102;
000059 put skip list('after ');
000060 put skip list('a2 =',a2 );
000061 put skip list('b2 =',b2 );
000062 put skip list('sub2 Leaving');
000063 return;
000064 end sub2;
****** **************************** Bottom of Data ****************************
and here is the result
Code:
********************************* TOP OF DATA **********************************
Main Starting
declared
x1 = 101
y1 = 102
x2 = 201
y2 = 202
assigned
x1 = 1101
y1 = 1102
x2 = 1201
y2 = 1202
sub1 Entered
at entry
a1 = 1101
b1 = 1102
aft
a1 = 2101
b1 = 2102
sub1 Leaving
after sub1
x1 = 2101
y1 = 2102
sub2 Entered
at entry
a2 = 1201
b2 = 1202
after
a2 = 2101
b2 = 2102
sub2 Leaving
after sub2
x2 = 1201
y2 = 1202
Main Ending
******************************** BOTTOM OF DATA ********************************
