---title:"mg_base64_decode()"decl_name:"mg_base64_decode"symbol_kind:"func"signature:|int mg_base64_decode(const unsigned char *s, int len, char *dst);---Decodes base64-encoded string `s`, `len` into the destination `dst`.The destination has to have enough space to hold the decoded buffer.Decoding stops either when all strings have been decoded or invalid ancharacter appeared.Destination is '\0'-terminated.Returns the number of decoded characters. On success, that should be equalto `len`. On error (invalid character) the return value is smaller then`len`.