从C调用python hello world函数,解析字符串参数
我使用中的代码创建了以下文件 callpython.c从C调用python hello world函数,解析字符串参数,python,c,python-2.7,Python,C,Python 2.7,我使用中的代码创建了以下文件 callpython.c #include </usr/include/python2.7/Python.h> int main(int argc, char *argv[]) { PyObject *pName, *pModule, *pDict, *pFunc; PyObject *pArgs, *pValue; int i; if (argc < 3) { fprintf(stderr,"U
#include </usr/include/python2.7/Python.h>
int
main(int argc, char *argv[])
{
PyObject *pName, *pModule, *pDict, *pFunc;
PyObject *pArgs, *pValue;
int i;
if (argc < 3) {
fprintf(stderr,"Usage: call pythonfile funcname [args]\n");
return 1;
}
Py_Initialize();
pName = PyString_FromString(argv[1]);
/* Error checking of pName left out */
//fprintf(stderr,"pName is %s\n", pName);
PyRun_SimpleString("import sys");
PyRun_SimpleString("sys.path.append(\".\")");
//PySys_SetArgv(argc, argv);
pModule = PyImport_Import(pName);
Py_DECREF(pName);
if (pModule != NULL) {
pFunc = PyObject_GetAttrString(pModule, argv[2]);
/* pFunc is a new reference */
if (pFunc && PyCallable_Check(pFunc)) {
pArgs = PyTuple_New(argc - 3);
for (i = 0; i < argc - 3; ++i) {
pValue = PyInt_FromLong(atoi(argv[i + 3]));
if (!pValue) {
Py_DECREF(pArgs);
Py_DECREF(pModule);
fprintf(stderr, "Cannot convert argument\n");
return 1;
}
/* iValue reference stolen here: */
PyTuple_SetItem(pArgs, i, pValue);
//PyTuple_SetItem(pArgs, i, argv[i + 3]);
}
pValue = PyObject_CallObject(pFunc, pArgs);
Py_DECREF(pArgs);
if (pValue != NULL) {
printf("Result of call: %ld\n", PyInt_AsLong(pValue));
Py_DECREF(pValue);
}
else {
Py_DECREF(pFunc);
Py_DECREF(pModule);
PyErr_Print();
fprintf(stderr,"Call failed\n");
return 1;
}
}
else {
if (PyErr_Occurred())
PyErr_Print();
fprintf(stderr, "Cannot find function \"%s\"\n", argv[2]);
}
Py_XDECREF(pFunc);
Py_DECREF(pModule);
}
else {
PyErr_Print();
fprintf(stderr, "Failed to load \"%s\"\n", argv[1]);
return 1;
}
Py_Finalize();
return 0;
}
我编译并运行callpython.c,如下所示
g++ -o callpython callpython.c -lpython2.7 -lm -L/usr/lib/python2.7/config && ./callpython helloworld helloworldFunc world
它不打印“Hello world”,而是打印“Hello 0”
为什么不将python函数参数解析为字符串?解决了这个问题。罪魁祸首就是这条线
pValue = PyInt_FromLong(atoi(argv[i + 3]));
它将每个参数作为一个整数解析到python脚本中
当替换为以下行时,它将每个参数解析为字符串
pValue = PyString_FromString(argv[i+3]);
我还没有真正理解pValue是如何工作的,但现在这就解决了问题。示例代码将参数解析为整数,如果您传递了一个字符串
atoi(“world”)
返回0,这就是您得到的整数:
/* Create tuple of the correct length for the arguments. */
pArgs = PyTuple_New(argc - 3);
for (i = 0; i < argc - 3; ++i) {
/* Convert each C argv to a C integer, then to a Python integer. */
pValue = PyInt_FromLong(atoi(argv[i + 3]));
if (!pValue) {
Py_DECREF(pArgs);
Py_DECREF(pModule);
fprintf(stderr, "Cannot convert argument\n");
return 1;
}
/* iValue reference stolen here: */
/* Store the Python integer in the tuple at the correct offset (i) */
PyTuple_SetItem(pArgs, i, pValue);
}
你试过使用调试器吗?您是否尝试使用更多参数运行该程序?@n.m.请查看我的答案。哈,您在我准备时回答了。@MarkTolonen谢谢,如果您可以在您的答案中添加对
PyTuple\u SetItem(pArgs,I,pValue)的解释代码>那太好了PyTuple_New()
创建一个大小等于函数参数数量的元组PyTuple_SetItem()
将元组的对应元素设置为为每个参数生成的pValue
对象。有关更多详细信息,请参阅文档中的。同时更新了我的答案。
/* Create tuple of the correct length for the arguments. */
pArgs = PyTuple_New(argc - 3);
for (i = 0; i < argc - 3; ++i) {
/* Convert each C argv to a C integer, then to a Python integer. */
pValue = PyInt_FromLong(atoi(argv[i + 3]));
if (!pValue) {
Py_DECREF(pArgs);
Py_DECREF(pModule);
fprintf(stderr, "Cannot convert argument\n");
return 1;
}
/* iValue reference stolen here: */
/* Store the Python integer in the tuple at the correct offset (i) */
PyTuple_SetItem(pArgs, i, pValue);
}
pValue = PyString_FromString(argv[i + 3]);