Wrapper to work around the lack of mkstemp() on mingw.
Also, tries to create file in /tmp first, if possible.
*prefix can be a character constant; *filename will be allocated internally.
@return file descriptor of opened file (or negative value corresponding to an
AVERROR code on error)
and opened file name in **filename.
@note On very old libcs it is necessary to set a secure umask before
calling this, av_tempfile() can't call umask itself as it is used in
libraries and could interfere with the calling application.
@deprecated as fd numbers cannot be passed saftely between libs on some platforms
Wrapper to work around the lack of mkstemp() on mingw. Also, tries to create file in /tmp first, if possible. *prefix can be a character constant; *filename will be allocated internally. @return file descriptor of opened file (or negative value corresponding to an AVERROR code on error) and opened file name in **filename. @note On very old libcs it is necessary to set a secure umask before calling this, av_tempfile() can't call umask itself as it is used in libraries and could interfere with the calling application. @deprecated as fd numbers cannot be passed saftely between libs on some platforms