WarpIN exports a number of REXX functions which may be used by any REXX macros. Until now these are the following:
rc=WirexxPutEnv(name, value)
Temporarily sets an environment variable within the WarpIN process. This can then be accessed by either WarpIN or another piece of REXX code, thus providing a means to exchange information. Note that even though REXX code can also set environment variables in other ways, those values will not be available for WarpIN, so you should always use this function to set environment variables. See remarks below.
value=WirexxGetEnv(name)
Returns the value of an environment variable. Reading environment variables can also be achieved in other ways with REXX, but if the variable was set by WarpIN, it will not be accessible unless you use WirexxGetEnv. One such variable is WI_ARCHIVE_PATH which contains the current path where WarpIN looks for any external archives (which is always the path where the first archive was read by WarpIN). Since the WarpIN environment will also contain all other environment variables inherited from the parent process or the CONFIG.SYS file, you should always use WirexxGetEnv to retrieve environment variables
rc=WirexxShowMessage(title, message, flags)
This function uses shows a message box with the provided title and message. flags is a numeric value which can be calculated by adding any of the following numeric codes:
0x0000 MB_OK               Message box contains an OK push button.
0x0001 MB_OKCANCEL         Message box contains both OK and CANCEL push
                           buttons.
0x0006 MB_CANCEL           Message box contains a CANCEL push button.
0x0007 MB_ENTER            Message box contains an ENTER push button.
0x0008 MB_ENTERCANCEL      Message box contains both ENTER and CANCEL push
                           buttons.
0x0002 MB_RETRYCANCEL      Message box contains both RETRY and CANCEL
                           push buttons.
0x0003 MB_ABORTRETRYIGNORE Message box contains ABORT, RETRY, and
                           IGNORE push buttons.
0x0004 MB_YESNO            Message box contains both YES and NO push
                           buttons.
0x0005 MB_YESNOCANCEL      Message box contains YES, NO, and CANCEL push
                           buttons.

0x0030 MB_ERROR            Message box contains a small red circle with a red
                           line across it.
0x0020 MB_ICONASTERISK     Message box contains an information (i) icon.
0x0040 MB_ICONEXCLAMATION  Message box contains an exclamation point (!)
                           icon.
0x0030 MB_ICONHAND         Message box contains a small red circle with a red
                           line across it.
0x0000 MB_ICONQUESTION     Message box contains a question mark (?) icon.
0x0010 MB_INFORMATION      Message box contains an information (i) icon.
0x0020 MB_NOICON           Message box is not to contain an icon.
0x0010 MB_QUERY            Message box contains a question mark (?) icon.
0x0020 MB_WARNING          Message box contains an exclamation point (!) icon.

0x0000 MB_DEFBUTTON1       The first button is the default selection. This is the
                           default case, if none of MB_DEFBUTTON1,
                           MB_DEFBUTTON2, and MB_DEFBUTTON3 is
                           specified.
0x0100 MB_DEFBUTTON2       The second button is the default selection.
0x0200 MB_DEFBUTTON3       The third button is the default selection.

0x0000 MB_APPLMODAL        Message box is application modal. This is the
                           default case. Its owner is disabled; therefore, do
                           not specify the owner as the parent if this option
                           is used.
0x1000 MB_SYSTEMMODAL      Message box is system modal.
0x4000 MB_MOVEABLE         Message box is moveable.

The value of rc indicates with which button the message box was closed:

9      MBID_ENTER  ENTER push button was selected
1      MBID_OK     OK push button was selected
2      MBID_CANCEL CANCEL push button was selected
3      MBID_ABORT  ABORT push button was selected
4      MBID_RETRY  RETRY push button was selected
5      MBID_IGNORE IGNORE push button was selected
6      MBID_YES    YES push button was selected
7      MBID_NO     NO push button was selected
0xffff MBID_ERROR  Function not successful; an error occurred.