• Martin Storsjö's avatar
    compat: msvc: Make sure the object files are included when linking statically · 769d921f
    Martin Storsjö authored
    If building libav with -MD in the cflags (for making the MSVC compiler
    generate code for using a dynamically linked libc), the system headers
    that declare strtod, snprintf and vsnprintf declare the functions as
    imported from a DLL. To hook up wrappers of our own for these functions,
    the function names are defined to avpriv_*, so that the calling code
    within libav calls the wrappers instead. Since these functions
    are declared to be imported from DLLs, the calling code expects to
    load them from DLL import function pointers (creating references to
    _imp__avpriv_strtod instead of directly to avpriv_strtod). If the
    libav libraries are not built as DLLs, no such function pointers (as
    the calling code expects) are created.
    
    The linker can fix this up automatically in some cases (producing
    warnings LNK4217 and LNK4049), if the object files are already
    included. By telling the linker to try to include those symbols
    (without the _imp prefix as the calling code ends up using),
    we get the object files included, so that the linker can do the
    automatic fixup. This is done via config.h, so that all (or at least
    most) of the object files in our libraries force including the compat
    files, to make sure they are included regardless of what files from our
    static libraries actually are included.
    Signed-off-by: 's avatarMartin Storsjö <martin@martin.st>
    769d921f
configure 121 KB