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| -rw-r--r-- | doc/manual.md | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/doc/manual.md b/doc/manual.md index 8075da18f..2f9506a87 100644 --- a/doc/manual.md +++ b/doc/manual.md @@ -8444,8 +8444,7 @@ is available and a literal dollar sign must be written as ``$$``. Bycopy pragma ------------- -The `bycopy` pragma can be applied to an object or tuple type and -instructs the compiler to pass the type by value to procs: +The `bycopy` pragma can be applied to an object or tuple type or a proc param. It instructs the compiler to pass the type by value to procs: ```nim type @@ -8453,14 +8452,19 @@ instructs the compiler to pass the type by value to procs: x, y, z: float ``` -The Nim compiler automatically determines whether a parameter is passed by value or by reference based on the parameter type's size. If a parameter must be passed by value or by reference, (such as when interfacing with a C library) use the bycopy or byref pragmas. +The Nim compiler automatically determines whether a parameter is passed by value or +by reference based on the parameter type's size. If a parameter must be passed by value +or by reference, (such as when interfacing with a C library) use the bycopy or byref pragmas. +Notice params marked as `byref` takes precedence over types marked as `bycopy`. Byref pragma ------------ -The `byref` pragma can be applied to an object or tuple type and instructs -the compiler to pass the type by reference (hidden pointer) to procs. - +The `byref` pragma can be applied to an object or tuple type or a proc param. +When applied to a type it instructs the compiler to pass the type by reference +(hidden pointer) to procs. When applied to a param it will take precedence, even +if the the type was marked as `bycopy`. When using the Cpp backend, params marked +as byref will translate to cpp references `&`. Varargs pragma -------------- |