The files which contain the executable code for a library’s shareable images should reside in the library directory and should be assigned logical names of the following standard form in order to identify them:
LIB_IMAGE | |
and/or | LIB_IMAGE_ADAM |
The first of these names refers to the stand-alone version of the library and the second to the ADAM version; they are required at run-time to identify the relevant shareable images to other executable images linked against them. If either version of the library does not exist, then the corresponding logical name should be left undefined. Other software may test for the existence or non-existence of either of these logical names in order to determine the availability of a particular version of the library.
In cases where there is no difference between the stand-alone and ADAM shareable images, both logical names may refer to the same image file. In general, however, these names will refer to different files, and it should always be assumed that the images will differ. In particular, it should be assumed that their transfer vectors will be incompatible, so that they may not be interchanged once an application has been linked with a particular version.
The logical names identifying a library’s shareable images should be defined in the system logical name table at system startup by means of suitable commands in the SSC:STARTUP.COM file, such as:
where LIB_IMAGE.EXE and LIB_IMAGE_ADAM.EXE are the shareable image files in question (these file names are recommended for future use but existing files need not be changed).