diff options
Diffstat (limited to 'docs/devel/qapi-code-gen.txt')
| -rw-r--r-- | docs/devel/qapi-code-gen.txt | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/docs/devel/qapi-code-gen.txt b/docs/devel/qapi-code-gen.txt index 53eaf01f34..43bd853e69 100644 --- a/docs/devel/qapi-code-gen.txt +++ b/docs/devel/qapi-code-gen.txt @@ -26,7 +26,7 @@ how the schemas, scripts, and resulting code are used. == QMP/Guest agent schema == A QAPI schema file is designed to be loosely based on JSON -(http://www.ietf.org/rfc/rfc7159.txt) with changes for quoting style +(http://www.ietf.org/rfc/rfc8259.txt) with changes for quoting style and the use of comments; a QAPI schema file is then parsed by a python code generation program. A valid QAPI schema consists of a series of top-level expressions, with no commas between them. Where @@ -752,6 +752,25 @@ gets its generated code guarded like this: #endif /* defined(HAVE_BAR) */ #endif /* defined(CONFIG_FOO) */ +Where a member can be defined with a single string value for its type, +it is also possible to supply a dictionary instead with both 'type' +and 'if' keys. + +Example: a conditional 'bar' member + +{ '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. + +Example: a conditional 'bar' enum member. + +{ '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. |