EXECUTE

The EXECUTE or PERFORM statement allows the currently executing program to pause and execute any other UNIX/NT program, including another jBC program or a TAFC command.

COMMAND SYNTAX

    EXECUTE | PERFORM expression { CAPTURING variable}  \
        { RETURNING | SETTING variable} { PASSLIST {expression}}  \
        { RTNLIST {variable}}{ PASSDATA variable} { RTNDATA variable}

Executes external programs or OS commands; you can intercept screen output and error messages from any program. Passes data, dynamic arrays and lists to executed jBC programs.

SYNTAX ELEMENTS

The PERFORMed expression can be formed from any TAFC construct. The system will not verify that the command exists before executing it. Use a new Bourne Shell to execute a command (sh) by default. The shell type can be changed by preceding the command with a CHAR(255) concatenated with either "k", "c", or "s" to signify the Korn shell, C shell or Bourne Shell.

Variables used to pass data to the executed program should have been assigned to a value before using. You can use any variable name to receive data.

CAPTURING variable

The capturing clause will capture any output that the executing program would normally send to the terminal screen and place it in the variable specified. A field mark in the variable replaces every newline normally sent to the terminal.

RETURNING variable or SETTING variable

The returning and setting clauses are identical. Both clauses will capture the output associated with any error messages the executing program issues. The first field of the variable will be set to the exit code of the program.

PASSLIST variable

The PASSLIST clause allows TAFC programs to exchange lists or dynamic arrays between them. The variable should contain the list that the program wishes to pass to the TAFC program it is executing. The program to be executed should be able to process lists, otherwise the list will just be ignored. If the variable name is not specified then the clause will pass the default select list to the executing program.

RTNLIST variable

If the executed program sets up a list then use the RTNLIST clause to place that list into a specified variable. It places the list in the default list variable if omitted.

PASSDATA variable

Passes the data in the specified variable to another jBC program, the executing jBC program should retrieve the data using the COLLECTDATA statement.

RTNDATA variable

The RTNDATA statement returns any data passed from an executing jBC program in the specified variable. The executing jBC program should use the RTNDATA statement to pass data back to the calling program.

NOTES

The clauses may be specified in any order within the statement but only one of each clause may exist.

TAFJ note 1: RTNLIST clause in EXECUTE 'SELECT' doesn't work.

TAFJ note 2: RETURNING clause in EXECUTE 'COUNT' doesn't work.

TAFJ note 3: EXECUTE of 2 commands delimited with @FM returns code from the first command, not from the second one. Example:

       EXECUTE 'SELECT F.SPF' :@FM: 'SAVE-LIST spf' CAPTURING output RETURNING ret_code
       CRT CONVERT(@FM:@VM:@SM, '^]\', ret_code)
       *  expected output: 241]1]sel_list]Savelist_msg
       *  output: 404]1]QLNUMSEL

TAFJ note 4: PASSLIST clause in EXECUTE doesn't work.

TAFJ note 5: EXIT() in EXECUTEd program stops the EXECUTing one as well.

TAFJ R22 note: EXECUTE 'COMO ON ...' and subsequent CRT statements create COMO file with the printed contents but on subsequent runs file is appended rather than recreated like it is in TAFC (under TAFJ R19 file wasn't even created).

Final TAFJ R22 note: use "DOS /c" under Windows or "SH -c" under Linux (keeping the case exactly as it is shown) to execute OS command:

        EXECUTE 'DOS /c C:\temenos\TAFJ\bin\tShow.bat ACCOUNT' CAPTURING output
        CRT '>>>'
        CHANGE @FM TO CHAR(10) IN output
        CRT output
        INPUT dummy

TAFJ R19/R23 note: EXECUTE doesn't output anything on the screen. Screen output can be taken via CAPTURING clause (works in R23 but not in R19).

EXAMPLE

       V.CMD = 'COUNT .'
       HUSH ON
       EXECUTE V.CMD RETURNING V.CNT
       HUSH OFF
       CRT V.CNT<1,2>     ;* e.g. 15

EXAMPLE 2

       EXECUTE 'SELECT F.TEMP' :@FM: 'SAVE.LIST TEMP-LIST'

EXAMPLE 3

       EXECUTE CHAR(255) : 'kecho $SHELL'   ;* /usr/bin/ksh

EXAMPLE 4

       EXECUTE 'df -m' CAPTURING V.OUTPUT
       LOOP
          REMOVE V.LINE FROM V.OUTPUT SETTING V.STATUS
          CRT '[' : V.LINE : ']'
          IF V.STATUS EQ 0 THEN BREAK
       REPEAT

Sample output of the last example:

     [Filesystem    MB blocks      Free %Used    Iused %Iused Mounted on]
     [/dev/hd4         512.00    276.03   47%    12020    16% /]
     [/dev/hd2        5120.00   1398.12   73%    67516    18% /usr]
     [/dev/hd9var      640.00     95.71   86%    13280    36% /var]
     [/dev/hd3         768.00    505.89   35%     8812     7% /tmp]
     [/dev/hd1         128.00    121.68    5%      185     1% /home]
     [/proc                 -         -    -         -     -  /proc]