libavutil: Deprecate av_fopen_utf8, provide an avpriv version

Since every DLL can use an individual CRT on Windows, having
an exported function that opens a FILE* won't work if that
FILE* is going to be used from a different DLL (or from user
application code).

Internally within the libraries, the issue can be worked around
by duplicating the function in all libraries (this already happened
implicitly because the function resided in file_open.c) and renaming
the function to ff_fopen_utf8 (so that it doesn't end up exported from
the DLLs) and duplicating it in all libraries that use it.

This makes the avpriv_fopen_utf8 / ff_fopen_utf8 function work in
the exact same way as the existing avpriv_open / ff_open, with the
same setup as introduced in e743e7ae6ee7e535c4394bec6fe6650d2b0dbf65.

That mechanism doesn't work for external users, thus deprecate the
existing function.

Signed-off-by: Martin Storsjö <martin@martin.st>

1 files changed, 6 insertions, 0 deletions

diff --git a/libavutil/avutil.h b/libavutil/avutil.h
index 4d633156d1..64b68bdbd3 100644
--- a/libavutil/avutil.h
+++ b/libavutil/avutil.h
@@ -331,12 +331,18 @@ unsigned av_int_list_length_for_size(unsigned elsize,
 #define av_int_list_length(list, term) \
     av_int_list_length_for_size(sizeof(*(list)), list, term)
 
+#if FF_API_AV_FOPEN_UTF8
 /**
  * Open a file using a UTF-8 filename.
  * The API of this function matches POSIX fopen(), errors are returned through
  * errno.
+ * @deprecated Avoid using it, as on Windows, the FILE* allocated by this
+ *             function may be allocated with a different CRT than the caller
+ *             who uses the FILE*. No replacement provided in public API.
  */
+attribute_deprecated
 FILE *av_fopen_utf8(const char *path, const char *mode);
+#endif
 
 /**
  * Return the fractional representation of the internal time base.