Glen Mabey
6bfcdfe8f9
working example of field enums
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4 years ago | |
|---|---|---|
| .. | ||
| README.md | 4 years ago | |
| field_enum_example.cpp | 4 years ago | |
| field_enum_example.pro | 4 years ago | |
| field_enum_example.proto | 4 years ago | |
README.md
Field Number Enumerations
In protobuf3, fields are by default optional.
When a field is not assigned (or, if it is not present in the version of the
.proto file that the sender was using), a default value will be assigned to
the field when it is deserialized by the message recipient.
This, however, leads to an ambiguity as to whether the field was assigned a
value which happened to be the default value, or whether it was not set at
all by the sender.
Preceeding the invocation of protoc with QT_PROTOBUF_OPTIONS="FIELDENUM"
results in additional enums being added to the .qpb.h files that are generated.
These can be useful to indicate which fields were actually set when the
message was created.
This could be compared to setting a field to NULL in a SQL database.