Server Guide

Function descriptions

This section describes the VASTART, VARUN, and VASTOP functions. Note that the function names are shown here in uppercase, which is appropriate for OS/390, though you should put the function names in lowercase for workstation environments.

VASTART

The VASTART function initializes and prepares the image for execution by the Smalltalk VM. The syntax of VASTART is:

CALL VASTART(imagename, &vhandle, &vstatus)

imagename
Specifies a data area containing an image name up to 8 characters in length.

vhandle
Address of the 4-byte binary area that is initialized by the VM upon successful image startup. A non-zero value indicates successful image startup.

vstatus
Address of the 4-byte binary area that is initialized by the VM. The VM places a binary return code in this field when errors occur. The possible values for vstatus are:
0
Successful
1-62
Smalltalk primitive error codes
801
Parameter error
802
Memory allocation error
803
Image initialization error
804
Image parse error
805
Invalid image handle
806
Call-in not supported in image
807
Parameter data error
808
Image not active
809
Unable to load VM

VARUN

The VARUN function initiates image execution by the Smalltalk VM. The syntax of VARUN is:

CALL VARUN(&vhandle, receiver, selector, ioareaLength, &ioarea, &vstatus, &vresult)

vhandle
Specifies a full word containing the vhandle returned from VASTART.

receiver
Specifies the data area containing the receiver character string. The receiver is the name of the Smalltalk class name. The receiver string must end in a single blank character. The maximum string length is 64 bytes.

selector
Specifies the data area containing the selector character string. The selector is the name of the Smalltalk class method. (Smalltalk instance methods are not supported.) The selector string must end in a single blank character. The maximum string length is 64 bytes.

ioareaLength
Specifies a full-word binary value containing the length of the ioarea storage area.

ioarea
Specifies the user-acquired or user-defined ioarea storage area containing the data to be passed from the called Smalltalk program.

vstatus
Specifies a full-word binary area that is initialized by the Smalltalk VM. The VM places a binary return code in this field. The possible values are the same as those for vstatus of VASTART.

vresult
Specifies a full-word binary area that is initialized by the virtual machine. The contents of this area are currently undefined.

VASTOP

The VASTOP function causes the Smalltalk VM to shut down the current image. The syntax of VASTOP is:

CALL VASTOP(&vhandle, &vstatus)

vhandle
Specifies a full word containing the vhandle returned from VASTART.

vstatus
Specifies a full-word binary area that is initialized by the virtual machine. The VM places a binary return code in this field. The possible values are the same as those for vstatus of VASTART.


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