>may i know what are the functions in this dll??? how can i use it??.. and actually... from where i can get this king of information for any dll??? how i know what function i can use.. and how to put the command?? can anyone teach me on this??
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There are a tremendous number of functions in SHELL32.DLL; it's a major component of the Win32 API. The documentation on the Win32 API is available as a part of the MSDN documentation on the Platform SDK; I strongly recommend that you buy a copy of the MSDN docs from Microsoft as a part of an MSDN subscription, or comes with the Visual Studio 6.0 product. While it's possible to discover all the entrypoints available for a .DLL, without the documentation on how the entrypoints are declared and behave, this information is useless.

There are no books written on the API from a VFP perspective; there are lots of books that cover the Win32 API in considerable detail. The MSDN docs are the canonical reference. If you're comformatable with VB, Dan Appleman's Visual Basic Programmer's Guide to the Win32 API is one of the best books on the topic available that is not targeted at the C programmer; it's well-written and syntactically, VB is much closer to VFP syntax than C would be if you're not familiar with C. From a C perspective, The Windows 98 Developer's Guide and The Windows NT Win32 API SuperBible are two references that I rely on heavily, but without some knowledge of C, they're not too approacable.

There are some entries in the FAQ here on UT that talk about the WIn32 API from a VFP perspective; George Tasker has written a brief overview that's a good starting point. If you're serious about making any significant use of API programming, you're going to have to get the Platform SDK documentation that's in the MSDN