SWIG 结构指针作为输出参数
SWIG struct pointer as output parameter
我有一个结构:
struct some_struct_s {
int arg1;
int arg2;
};
我有一个 C 函数:
int func(some_struct_s *output);
两者都 %included
到我的 SWIG 文件中。
我希望 some_struct_s *output
被视为输出参数。 Python 示例:
int_val, some_struct_output = func()
"Output parameters" 包含在 POD 类型的手册中(第 10.1.3 节),但不包含非 POD 类型。
如何告诉 SWIG 我希望 some_struct_s *output
作为输出参数?
11.5.7 "argout" typemap
The "argout" typemap is used to return values from arguments. This is most commonly used to write wrappers for C/C++ functions that need to return multiple values. The "argout" typemap is almost always combined with an "in" typemap---possibly to ignore the input value....
这是您的代码的完整示例(为简洁起见没有错误检查):
%module test
// Declare an input typemap that suppresses requiring any input and
// declare a temporary stack variable to hold the return data.
%typemap(in,numinputs=0) some_struct_s* (some_struct_s tmp) %{
= &tmp;
%}
// Declare an output argument typemap. In this case, we'll use
// a tuple to hold the structure data (no error checking).
%typemap(argout) some_struct_s* (PyObject* o) %{
o = PyTuple_New(2);
PyTuple_SET_ITEM(o,0,PyLong_FromLong(->arg1));
PyTuple_SET_ITEM(o,1,PyLong_FromLong(->arg2));
$result = SWIG_Python_AppendOutput($result,o);
%}
// Instead of a header file, we'll just declare this code inline.
// This includes the code in the wrapper, as well as telling SWIG
// to create wrappers in the target language.
%inline %{
struct some_struct_s {
int arg1;
int arg2;
};
int func(some_struct_s *output)
{
output->arg1 = 1;
output->arg2 = 2;
return 0;
}
%}
演示如下。请注意,int
return 零值以及作为元组的输出参数被 return 编辑为列表。
>>> import test
>>> test.func()
[0, (1, 2)]
如果您不想要类型映射,您还可以注入代码来创建对象并return它对用户隐藏:
%module test
%rename(_func) func; // Give the wrapper a different name
%inline %{
struct some_struct_s {
int arg1;
int arg2;
};
int func(struct some_struct_s *output)
{
output->arg1 = 1;
output->arg2 = 2;
return 0;
}
%}
// Declare your interface
%pythoncode %{
def func():
s = some_struct_s()
r = _func(s)
return r,s
%}
演示:
>>> import test
>>> r,s=test.func()
>>> r
0
>>> s
<test.some_struct_s; proxy of <Swig Object of type 'some_struct_s *' at 0x000001511D70A880> >
>>> s.arg1
1
>>> s.arg2
2
如果您仔细 select SWIG 宏:
,您可以使类型映射语言不可知
%module test
%typemap(in,numinputs=0) struct some_struct_s *output %{
= malloc(sizeof(struct some_struct_s));
%}
%typemap(argout) struct some_struct_s* output {
%append_output(SWIG_NewPointerObj(,_descriptor,1));
}
%inline %{
struct some_struct_s {
int arg1;
int arg2;
};
int func(struct some_struct_s *output)
{
output->arg1 = 1;
output->arg2 = 2;
return 0;
}
%}
演示:
>>> import test
>>> r,s=test.func()
>>> r
0
>>> s
<test.some_struct_s; proxy of <Swig Object of type 'some_struct_s *' at 0x000001DD0425A700> >
>>> s.arg1
1
>>> s.arg2
2
我有一个结构:
struct some_struct_s {
int arg1;
int arg2;
};
我有一个 C 函数:
int func(some_struct_s *output);
两者都 %included
到我的 SWIG 文件中。
我希望 some_struct_s *output
被视为输出参数。 Python 示例:
int_val, some_struct_output = func()
"Output parameters" 包含在 POD 类型的手册中(第 10.1.3 节),但不包含非 POD 类型。
如何告诉 SWIG 我希望 some_struct_s *output
作为输出参数?
11.5.7 "argout" typemap
The "argout" typemap is used to return values from arguments. This is most commonly used to write wrappers for C/C++ functions that need to return multiple values. The "argout" typemap is almost always combined with an "in" typemap---possibly to ignore the input value....
这是您的代码的完整示例(为简洁起见没有错误检查):
%module test
// Declare an input typemap that suppresses requiring any input and
// declare a temporary stack variable to hold the return data.
%typemap(in,numinputs=0) some_struct_s* (some_struct_s tmp) %{
= &tmp;
%}
// Declare an output argument typemap. In this case, we'll use
// a tuple to hold the structure data (no error checking).
%typemap(argout) some_struct_s* (PyObject* o) %{
o = PyTuple_New(2);
PyTuple_SET_ITEM(o,0,PyLong_FromLong(->arg1));
PyTuple_SET_ITEM(o,1,PyLong_FromLong(->arg2));
$result = SWIG_Python_AppendOutput($result,o);
%}
// Instead of a header file, we'll just declare this code inline.
// This includes the code in the wrapper, as well as telling SWIG
// to create wrappers in the target language.
%inline %{
struct some_struct_s {
int arg1;
int arg2;
};
int func(some_struct_s *output)
{
output->arg1 = 1;
output->arg2 = 2;
return 0;
}
%}
演示如下。请注意,int
return 零值以及作为元组的输出参数被 return 编辑为列表。
>>> import test
>>> test.func()
[0, (1, 2)]
如果您不想要类型映射,您还可以注入代码来创建对象并return它对用户隐藏:
%module test
%rename(_func) func; // Give the wrapper a different name
%inline %{
struct some_struct_s {
int arg1;
int arg2;
};
int func(struct some_struct_s *output)
{
output->arg1 = 1;
output->arg2 = 2;
return 0;
}
%}
// Declare your interface
%pythoncode %{
def func():
s = some_struct_s()
r = _func(s)
return r,s
%}
演示:
>>> import test
>>> r,s=test.func()
>>> r
0
>>> s
<test.some_struct_s; proxy of <Swig Object of type 'some_struct_s *' at 0x000001511D70A880> >
>>> s.arg1
1
>>> s.arg2
2
如果您仔细 select SWIG 宏:
,您可以使类型映射语言不可知%module test
%typemap(in,numinputs=0) struct some_struct_s *output %{
= malloc(sizeof(struct some_struct_s));
%}
%typemap(argout) struct some_struct_s* output {
%append_output(SWIG_NewPointerObj(,_descriptor,1));
}
%inline %{
struct some_struct_s {
int arg1;
int arg2;
};
int func(struct some_struct_s *output)
{
output->arg1 = 1;
output->arg2 = 2;
return 0;
}
%}
演示:
>>> import test
>>> r,s=test.func()
>>> r
0
>>> s
<test.some_struct_s; proxy of <Swig Object of type 'some_struct_s *' at 0x000001DD0425A700> >
>>> s.arg1
1
>>> s.arg2
2