Parse and evaluate an expression.
Note, this is significantly slower than av_expr_eval().
@param res a pointer to a double where is put the result value of
the expression, or NAN in case of error
@param s expression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)"
@param const_names NULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0}
@param const_values a zero terminated array of values for the identifiers from const_names
@param func1_names NULL terminated array of zero terminated strings of funcs1 identifiers
@param funcs1 NULL terminated array of function pointers for functions which take 1 argument
@param func2_names NULL terminated array of zero terminated strings of funcs2 identifiers
@param funcs2 NULL terminated array of function pointers for functions which take 2 arguments
@param opaque a pointer which will be passed to all functions from funcs1 and funcs2
@param log_ctx parent logging context
@return >= 0 in case of success, a negative value corresponding to an
AVERROR code otherwise
Parse and evaluate an expression. Note, this is significantly slower than av_expr_eval().
@param res a pointer to a double where is put the result value of the expression, or NAN in case of error @param s expression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)" @param const_names NULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0} @param const_values a zero terminated array of values for the identifiers from const_names @param func1_names NULL terminated array of zero terminated strings of funcs1 identifiers @param funcs1 NULL terminated array of function pointers for functions which take 1 argument @param func2_names NULL terminated array of zero terminated strings of funcs2 identifiers @param funcs2 NULL terminated array of function pointers for functions which take 2 arguments @param opaque a pointer which will be passed to all functions from funcs1 and funcs2 @param log_ctx parent logging context @return >= 0 in case of success, a negative value corresponding to an AVERROR code otherwise