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[SOLVED] Difference between DLLs ended with d or without d

  • Hi!

    I would like to know the difference between DLLs ended with d or without d (i.e. QtCore5.dll and QtCore5d.dll). I am developing and application which suddenly has changed it dependencies to the d version of DLLs and I don`t know the reason.

    Thanks in advance

  • Lifetime Qt Champion

    Hi and welcome to devnet,

    The d suffix is for the debug libraries, when you release an application you link to the release version of the library. Note that depending on the OS the suffix might change to e.g. _debug

    Hope it helps

  • Just a little addendum: The "Release" versions are built with various compiler optimizations enabled and without debug symbols, which makes the code run (much) faster but makes debugging as well as reverse engineering more difficult. On the other hand, the "Debug" versions have most compiler optimizations disabled and they include debug symbols, so you can (for example) get meaningful stacktraces in your debugger. You want to make sure to only deploy your software with the "Release" versions ;-)

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