@param expr a pointer where is put an AVExpr containing the parsed
value in case of successful parsing, or NULL otherwise.
The pointed to AVExpr must be freed with av_expr_free() by the user
when it is not needed anymore.
@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 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 log_ctx parent logging context
@return >= 0 in case of success, a negative value corresponding to an
AVERROR code otherwise
Parse an expression.
@param expr a pointer where is put an AVExpr containing the parsed value in case of successful parsing, or NULL otherwise. The pointed to AVExpr must be freed with av_expr_free() by the user when it is not needed anymore. @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 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 log_ctx parent logging context @return >= 0 in case of success, a negative value corresponding to an AVERROR code otherwise