如何使用命令行驱动的应用程序的python3capi?-Howdoyouusethepython3capiforacommandlinedrivenapp?

I've been using a custom build as a replacement for virtualenv for a while now, and it's brillant. It takes longer to build, but it actually works, and it never screws up.

我一直在使用自定义的构建来代替virtualenv，现在它是布里兰特。它需要更长的时间来构建，但它实际上是有效的，而且它从不出错。

Part of this in a simple python wrapper that adds some specific folders to the library path, which I've found very useful. The code for it is trivial:

在一个简单的python包装器中，将一些特定的文件夹添加到库路径中，这是非常有用的。它的代码很简单:

#include 
#include 
#include 

int main(int argc, char *argv[]) {

  /* Setup */
  Py_SetProgramName(argv[0]);
  Py_Initialize();
  PySys_SetArgv(argc, argv);

  /* Add local path */
  PyObject *sys = PyImport_ImportModule("sys");
  PyObject *path = PyObject_GetAttrString(sys, "path");

  /* Custom path */
  char *cwd = nrealpath(argv[0]);
  char *libdir = nstrpath(cwd, "python_lib", NULL);
  PyList_Append(path, PyString_FromString(libdir));
  free(cwd);
  free(libdir);

  /* Run the 'main' module */
  int rtn = Py_Main(argc, argv); // <-- Notice the command line arguments.
  Py_Finalize();

  return rtn;
}

So, moving to python3 is good right? So...

那么，移动到python3是很好的，对吧?所以…

I dutifully replaced the call to PyString_FromString() with PyByte_FromString() and tried to recompile, but it raises errors:

我使用PyByte_FromString()将调用替换为PyString_FromString()，并试图重新编译，但它会引起错误:

/Users/doug/env/src/main.c:8:21: error: incompatible pointer types passing 'char *' to parameter of type 'wchar_t *' (aka 'int *')
      [-Werror,-Wincompatible-pointer-types]
  Py_SetProgramName(argv[0]);
                    ^~~~~~~
/Users/doug/projects/py-sdl2/py3/include/python3.3m/pythonrun.h:25:45: note: passing argument to parameter here
PyAPI_FUNC(void) Py_SetProgramName(wchar_t *);
                                            ^
/Users/doug/env/src/main.c:10:23: error: incompatible pointer types passing 'char **' to parameter of type 'wchar_t **' (aka 'int **')
      [-Werror,-Wincompatible-pointer-types]
  PySys_SetArgv(argc, argv);
                      ^~~~
/Users/doug/projects/py-sdl2/py3/include/python3.3m/sysmodule.h:12:47: note: passing argument to parameter here
PyAPI_FUNC(void) PySys_SetArgv(int, wchar_t **);
                                              ^
/Users/doug/env/src/main.c:24:27: error: incompatible pointer types passing 'char **' to parameter of type 'wchar_t **' (aka 'int **')
      [-Werror,-Wincompatible-pointer-types]
  int rtn = Py_Main(argc, argv);
                          ^~~~
/Users/doug/projects/py-sdl2/py3/include/python3.3m/pythonrun.h:148:45: note: passing argument to parameter 'argv' here
PyAPI_FUNC(int) Py_Main(int argc, wchar_t **argv);
                                            ^
3 errors generated.
make[2]: *** [CMakeFiles/python.dir/src/main.c.o] Error 1
make[1]: *** [CMakeFiles/python.dir/all] Error 2
make: *** [all] Error 2

As you can see from the error, wchar_t is used instead of char *.

从错误中可以看出，使用wchar_t代替char *。

How are you supposed to use this api?

你如何使用这个api?

I see there are a few examples of doing this, for example: http://svn.python.org/projects/python/tags/r32rc2/Python/frozenmain.c

我看到有一些这样做的例子，例如:http://svn.python.org/projects/python/tags/r32rc2/Python/frozenmain.c。

seriously?

严重吗?

My 29 line program has to become a 110 line monster full of #ifdefs?

我的29行程序必须变成一个110线怪物，满是#ifdefs?

Am I misunderstanding, or has the python3 c api really become this ridiculously difficult to use?

我是否误解了，或者python3 c api真的变得如此难以使用?

Surely I'm missing some obvious convenience function which does this for you, in a simple, portable and cross platform way?

我肯定错过了一些显而易见的便利功能，这是为你做的，在一个简单，便携，跨平台的方式?

4 个解决方案

wchar_t *program = Py_DecodeLocale(argv[0], NULL);
Py_SetProgramName(program);

#include 
#include 
#include 

int main(int argc, char *argv[]) {

  /* These have to be wchar_t */
  char *str_program_name = argv[0];
  char **str_argv = argv;

  /* For ever stupid reason, these don't need to be wchar_t * */
  char *_sys = "sys";
  char *_libdir = "lib";
  char *_path = "path";
  char *_dot = ".";

#if PY_MAJOR_VERSION >= 3
  wchar_t **_argv = nstrws_array(argc, str_argv);
  wchar_t *_program_name = nstrws_convert(str_program_name);
#else
  char **_argv = str_argv;
  char *_program_name = str_program_name;
#endif

  /* Setup */
  Py_SetProgramName(_program_name);
  Py_Initialize();

  /* Add local path */
#if PY_MAJOR_VERSION >= 3
  PyObject *sys = PyImport_ImportModule(_sys);
  PyObject *path = PyObject_GetAttrString(sys, _path);
  PyList_Append(path, PyBytes_FromString(_dot));
  PyList_Append(path, PyBytes_FromString(_libdir));
#else
  PyObject *sys = PyImport_ImportModule(_sys);
  PyObject *path = PyObject_GetAttrString(sys, _path);
  PyList_Append(path, PyString_FromString(_dot));
  PyList_Append(path, PyString_FromString(_libdir));
#endif

  /* Run the 'main' module */
  int rtn = Py_Main(argc, _argv);
  Py_Finalize();

#if PY_MAJOR_VERSION >= 3
  nstrws_dispose(argc, _argv);
  free(_program_name);
#endif

  return rtn;
}

/** Unix-like platform char * to wchar_t conversion. */
wchar_t *nstrws_convert(char *raw) {
  wchar_t *rtn = (wchar_t *) calloc(1, (sizeof(wchar_t) * (strlen(raw) + 1)));
  setlocale(LC_ALL,"en_US.UTF-8"); // Unless you do this python 3 crashes.
  mbstowcs(rtn, raw, strlen(raw));
  return rtn;
}

/** Dispose of an array of wchar_t * */
void nstrws_dispose(int count, wchar_t ** values) {
  for (int i = 0; i 

#include 

/** Windows char * to wchar_t conversion. */
wchar_t *nstrws_convert(char *raw) {
  int size_needed = MultiByteToWideChar(CP_UTF8, 0, raw, -1, NULL, 0);
  wchar_t *rtn = (wchar_t *) calloc(1, size_needed * sizeof(wchar_t));
  MultiByteToWideChar(CP_UTF8, 0, raw, -1, rtn, size_needed);
  return rtn;
}

Py_SetProgramName((wchar_t*)argv[0]);

wchar_t progname[FILENAME_MAX + 1];
mbstowcs(progname, argv[0], strlen(argv[0]) + 1);
Py_SetProgramName(progname);

#include "sys/param.h"