прикрепите к сообщению одно поле (Attach a single field to a message)
Возвращаемое значение (Return value)
On success, this call returns 0 or a positive integer. On
failure, it returns a negative errno-style error code.
Errors
Returned errors may indicate the following problems:
-EINVAL
Specified parameter is invalid.
-EPERM
Message has been sealed.
-ESTALE
Message is in invalid state.
-ENXIO
Message cannot be appended to.
-ENOMEM
Memory allocation failed.
