Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com> --- docs/devel/qapi-code-gen.txt | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+)
diff --git a/docs/devel/qapi-code-gen.txt b/docs/devel/qapi-code-gen.txt index f58d62686a..479b755609 100644 --- a/docs/devel/qapi-code-gen.txt +++ b/docs/devel/qapi-code-gen.txt @@ -682,6 +682,44 @@ Example: Red Hat, Inc. controls redhat.com, and may therefore add a downstream command __com.redhat_drive-mirror. +=== Configuring the schema === + +Top-level QAPI expressions and various type expressions listed below +can take an 'if' key. The value must be a string or a list of +string. The corresponding generated code will then guard the inclusion +of that member in the larger struct or function with #if IFCOND +(or several #if lines for a list), where IFCOND is the value of the +'if' key. + +'struct', 'enum', 'union', 'alternate', 'command' and 'event' +top-level QAPI expressions can take an 'if' keyword like: + +{ 'struct': 'IfStruct', 'data': { 'foo': 'int' }, + 'if': 'defined(IFCOND)' } + +Where a member can normally be defined with a single string value as its +type, it is also possible to supply a dictionary with both 'type' and +'if' keys. + +{ 'struct': 'IfStruct', 'data': + { 'foo': 'int', + 'bar': { 'type': 'int', 'if': 'defined(IFCOND)'} } } + +An enum value can be replaced by a dictionary with a 'name' and a 'if' +key: + +{ 'enum': 'IfEnum', 'data': + [ 'foo', + { 'name' : 'bar', 'if': 'defined(IFCOND)' } ] } + +Please note that you are responsible to ensure that the C code will +compile with an arbitrary combination of conditions, since the +generators are unable to check it at this point. + +The presence of 'if' keys in the schema is reflected through to the +introspection output depending on the build configuration. + + == Client JSON Protocol introspection == Clients of a Client JSON Protocol commonly need to figure out what -- 2.16.0.rc1.1.gef27df75a1