New FAQ entry on ASCII/Unicode functions in Windows

[ringerc]

Q: On Windows, MSDN shows that TheFuncName is in somelib.dll but JNA throws UnsatisifiedLinkError: The specified procedure could not be found.

A: Make sure you're on a version of Windows that contains the function.

A: Some windows functions are documented as TheFuncName but are actually implemented as TheFuncNameA and TheFuncNameW in the library. You can see this with Dependency Walker (depends.exe) from http://dependencywalker.com when you open the DLL. JNA won't automatically resolve the wide-string variant, so you should explicitly declare the wide-string name variant or use a FunctionMapper like W32APIFunctionMapper.

[ringerc]

See also related Stack Overflow post with example: http://stackoverflow.com/q/26644491/398670

[dblock]

You should contribute this to the JNA documentation.

[twall]

This is useful, thanks.

It’s preferable to use a combination of TypeMapper and FunctionMapper (see com.sun.jna.win32.W32APIOptions.DEFAULT_OPTIONS) so that you can leave off the “-A” or “-W” suffix (you never need to use both simultaneously) and use “String” rather than explicit “WString”.

On Oct 29, 2014, at 11:10 PM, Craig Ringer [email protected] wrote:

Q: On Windows, MSDN shows that TheFuncName is in somelib.dll but JNA throws UnsatisifiedLinkError: The specified procedure could not be found.

A: Make sure you're on a version of Windows that contains the function.

A: Some windows functions are documented as TheFuncName but are actually implemented as TheFuncNameA and TheFuncNameW in the library. You can see this with Dependency Walker (depends.exe) from http://dependencywalker.com when you open the DLL. JNA won't automatically resolve the wide-string variant, so you should explicitly declare the wide-string name variant or use a FunctionMapper.

—
Reply to this email directly or view it on GitHub.