RE: CLASSPATH Api's?

["Simon Coulter" <shc@xxxxxxxxxxxxxxxxx>]

Hello Geert,

You should ask these questions on the list so everyone benefits from the
answer.  ALthough this is no no longer a Java question and should be
directed to the RPG400-L list.

C has no idea about fixed-length strings.  Most C functions either require
you to pass the length of the data as a separate parameter or they expect
null-terminated strings.  Any C function that has a char * string
definition and no length integer will need a null added to the end of the
character data.

You can do that in two ways:  If you define the RPG prototype as a pointer
with OPTIONS(*STRING) as you have done then RPG puts a null on the end BUT
it doesn't trim the data.  You can define the RPG prototype as accepting a
*VARSIZE variable and put the terminating null on yourself.  Neither
approach is ideal but if you use the keyword VALUE or CONST you don't need
to stuff about with the based pointer -- let the compiler do the hard
work.  You can also use an expression so you could wrap %trim around the
variable e.g., eval envptr = getenv(%trim(envvar))

RPG has no idea about null-terminated strings so when you tell it to
display VALUE it shows all 250 bytes.  Even though you use %TRIM that will
only trim blanks and there could be all sorts of crap after the
terminating null.  However there is a %STR BIF that will extract a
null-terminated string.

getenv gives you a pointer to a null-terminated string.  You must
determine the length of that string.  The easiest way to do that is to use
the %STR BIF.  You could also call the C function strlen() which returns
the length of the string not counting the null.  Then you can simply
%SUBST the data.

Also, although getenv is exported from the C-runtime it no longer appears
to be used.  The C headers eventually map getenv to Qp0zGetEnvNoCCSID
which is what I use.  The corresponding putenv function is not exported at
all and it maps to Qp0zPutEnvNoCCSID.  I couldn't get your prototype to
work when passing a literal so I changed it.

I have attached two versions of the code: one using %STR and the other
using strlen(); take your pick.

Here is a fixed version of your code that uses %STR:

H DFTACTGRP(*NO) BNDDIR('QC2LE') ACTGRP(*NEW)

DGetEnvVar        PR              *   Extproc('Qp0zGetEnvNoCCSID')
D   Envp                          *   Value options(*string)

D  Valuep         S               *
D  Value          S            250A   Based(Valuep)
D  Msg1           S             50A
D  Msg2           S             50A

C                   Eval      Valuep=GetEnvVar('CLASSPATH')

C                   If        Valuep = *NULL
C                   Movel(p)  'NULL'        Msg1
C                   Else
C                   EVAL      msg1 = %str(valuep: %size(value))
C                   Eval      Msg2 =%char(%len(%trim(msg1)))
C     Msg2          dsply
C                   Endif

C     Msg1          dsply
C                   Eval      *inlr=*on

Here is a fixed version of your code that uses strlen():

H DFTACTGRP(*NO) BNDDIR('QC2LE') ACTGRP(*NEW)

DGetEnvVar        PR              *   Extproc('Qp0zGetEnvNoCCSID')
D   Envp                          *   Value options(*string)
DPutEnvVar        PR            10I 0 Extproc('Qp0zPutEnvNoCCSID')
D   Envp                          *   Value options(*string)
D strlen          PR            10I 0 EXTPROC('__strlen')
D   string                        *   VALUE OPTIONS(*STRING)

D  Valuep         S               *
D  Value          S            250A   Based(Valuep)
D  Msg1           S             50A
D  Msg2           S             50A

C                   Eval      Valuep=GetEnvVar('CLASSPATH')

C                   If        Valuep = *NULL
C                   Movel(p)  'NULL'        Msg1
C                   Else
C                   Eval      Msg2 =%char(strlen(valuep))
C     Msg2          dsply
C                   EVAL      msg1 = %SUBST(value:1:strlen(valuep))
C                   Endif

Regards,
Simon Coulter.

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