Question

CBL_GC_HOSTED provides access to the following C hosted variables:

• argc  to binary-long by value
• argv  to pointer to char **
• stdin, stdout, stderr  to pointer
• errno  giving address of errno in pointer to binary-long, use based for more direct access

and conditional access to the following variables:

• tzname  pointer to pointer to array of two char pointers
• timezone  C long, will be seconds west of UTC
• daylight  C int, will be 1 during daylight savings

System will need to HAVE_TIMEZONE defined for these to return anything meaningful. Attempts made when they are not available return 1 from CBL_GC_HOSTED.

It returns 0 when match, 1 on failure, case matters as does length, arg won’t match.

The usage of this system routine is described by the following example.

HOSTED identification division.
       program-id. hosted.
       data division.
       working-storage section.
       01 argc  usage binary-long.
       01 argv  usage pointer.

       01 stdin usage pointer.
       01 stdout usage pointer.
       01 stderr usage pointer.

       01 errno usage pointer.
       01 err   usage binary-long based.

       01 domain usage float-long value 3.0.

       01 tzname usage pointer.
       01 tznames usage pointer based.
          05 tzs usage pointer occurs 2 times.

       01 timezone   usage binary-long.
       01 daylight   usage binary-short.


      *> Testing CBL_GC_HOSTED
       procedure division.
       call "CBL_GC_HOSTED" using stdin "stdin"
       display "stdin                : " stdin
       call "feof" using by value stdin
       display "feof stdin           : " return-code

       call "CBL_GC_HOSTED" using stdout "stdout"
       display "stdout               : " stdout
       call "fprintf" using by value stdout by content "Hello" & x"0a"

       call "CBL_GC_HOSTED" using stderr "stderr"
       display "stderr               : " stderr
       call "fprintf" using by value stderr by content "on err" & x"0a"

       call "CBL_GC_HOSTED" using argc "argc"
       display "argc                 : " argc

       call "CBL_GC_HOSTED" using argv "argv"
       display "argv                 : " argv

       call "args" using by value argc argv

       call "CBL_GC_HOSTED" using errno "errno"
       display "&errno               : " errno
       set address of err to errno
       display "errno                : " err
       call "acos" using by value domain
       display "errno after acos(3.0): " err ", EDOM is 33"

       call "CBL_GC_HOSTED" using argc "arg"
       display "'arg' lookup         : " return-code
       call "CBL_GC_HOSTED" using null "argc"
       display "null with argc       : " return-code
       display "argc is still        : " argc


       *> the following only returns zero if the system has HAVE_TIMEZONE set

       call "CBL_GC_HOSTED" using daylight "daylight "
       display "'timezone' lookup    : " return-code

       if return-code not = 0
          display "system doesn't has timezone"
       else

          display "timezone is          : " timezone

          call "CBL_GC_HOSTED" using daylight "daylight "
          display "'daylight' lookup    : " return-code
          display "daylight is          : " daylight

          set environment "TZ" to "PST8PDT"
          call static "tzset" returning omitted on exception continue end-call

          call "CBL_GC_HOSTED" using tzname "tzname"
          display "'tzname' lookup      : " return-code

          *> tzs(1) will point to z"PST" and tzs(2) to z"PDT"
          if return-code equal 0 and tzname not equal null then
              set address of tznames to tzname
              if tzs(1) not equal null then
                 display "tzs #1               : " tzs(1)
              end-if
              if tzs(2) not equal null then
                 display "tzs #2               : " tzs(2)
              end-if
          end-if

       end-if

       goback.
       end program hosted.