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Loading DLLs z/OS Language Environment Programming Guide for 64-bit Virtual Addressing Mode SA38-0689-00 |
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When you load an AMODE 64 DLL for the first time, either implicitly or via an explicit dllload() or dlopen(), writable static area is initialized. If the DLL is written in C++ and contains static objects, then their constructors are run. You can load DLLs from a z/OS UNIX HFS as well as from conventional data sets. The following list specifies the order of a search for unambiguous and ambiguous file names.
Recommendation: All DLLs used by an application should be referred to by unique names, whether ambiguous or not. Using multiple names for the same DLL (for example, aliases or symlinks) may result in a decrease in DLL load performance. The use of HFS symbolic links by themselves will not degrade performance, as long as the application refers to the DLL solely through the symbolic link name. To help ensure this, when building an application with implicit DLL references always use the same side deck for each DLL. Also, make sure that explicit DLL references with dllload() specify the same DLL name (case matters for HFS loads). Changing the search order for DLLs while the application is running (for example, changing LIBPATH) may result in errors if ambiguous file names are used. |
Copyright IBM Corporation 1990, 2014
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