cmake encuentra mal las libs de python

Question

Soy nuevo en CMake y tengo problemas para entender algunos conceptos de uso.

Voy a llamar a un script en Python, a partir de un programa en C++:

#include <Python.h> 
... 
Py_Initialize(); 
PyRun_SimpleFile(...); 
Py_Finalize(); 

Las entradas cmake correspondientes en mi archivo cmake son:

FIND_PACKAGE(PythonLibs REQUIRED) 
... 
TARGET_LINK_LIBRARIES(MyApplication ${PYTHON_LIBRARIES}) 

Esto funciona siempre y cuando mi pitón escritura ISN' t usando cualquier módulo instalado en el directorio site-packages, de lo contrario obtengo un ImportError. This question muestra cómo encontrar la ubicación del directorio de paquetes de sitio con CMake, pero ¿qué debo decirle a CMake que haga con él?

EDITAR: Problema resuelto. Resulta que FIND_PACKAGE (PythonLibs) encuentra una instalación de python diferente de lo que estoy usando normalmente (/usr/local/lib/libpython2.7.dylib en lugar de /Library/Frameworks/Python.framework/Versions/2.7/lib/libpython2. 7.dylib - Estoy en mac), que es como obtengo los módulos de python estándar, pero ninguno que instalé yo mismo. Para cambiar la PYTHONPATH a la normalidad, agregué

try: 
    import some_package 
except ImportError: 
    if "my_python_path" in sys.path: raise 
    sys.path.append("my_python_path") 

en la parte superior de mi secuencia de comandos python.

Answer 1

Se puede decir cmake dónde encontrar esta PythonLibs especificando la ruta de acceso a bibliotecas como pitón esto:

cmake -DPYTHON_LIBRARIES=/Library/Frameworks/Python.framework/Versions/2.7/lib/libpython2.7.dylib . 

esto continuación, establezca la $ {} PYTHON_LIBRARIES dentro cmake por el camino correcto.

para saber qué otras opciones posibles (además PYTHON_LIBRARIES) se puede dar a cmake (con la opción -DARG) intente ejecutar

ccmake . 

A continuación, pulse c configurar y t para las opciones avanzadas.

Por ejemplo, es posible que también desee establecer

-DPYTHON_LIBRARY='/softwarepath/Python/Python2.7/lib/libpython2.7.so' 
-DPYTHON_INCLUDE='/softwarepath/Python/Python2.7/include' 

Answer 2

En este momento está integrando python en su programa. ¿Llamaste a Py_Initialize() antes de PyRun_SimpleFile? Eche un vistazo al Embedding Python in Another Application.

Py_Initialize() configurará sys.path y se requiere para establecer el entorno python.

Si puede averiguar dónde está instalado python, es posible configurar python home para anular los cálculos de ruta de python. Utilice Py_SetPythonHome() antes de Py_Initialize().

En los sistemas operativos de tipo POSIX, aquí es un comentario en getpath.c (CPython aplicación de resolver path):

/* Search in some common locations for the associated Python libraries. 
* 
* Two directories must be found, the platform independent directory 
* (prefix), containing the common .py and .pyc files, and the platform 
* dependent directory (exec_prefix), containing the shared library 
* modules. Note that prefix and exec_prefix can be the same directory, 
* but for some installations, they are different. 
* 
* Py_GetPath() carries out separate searches for prefix and exec_prefix. 
* Each search tries a number of different locations until a ``landmark'' 
* file or directory is found. If no prefix or exec_prefix is found, a 
* warning message is issued and the preprocessor defined PREFIX and 
* EXEC_PREFIX are used (even though they will not work); python carries on 
* as best as is possible, but most imports will fail. 
* 
* Before any searches are done, the location of the executable is 
* determined. If argv[0] has one or more slashes in it, it is used 
* unchanged. Otherwise, it must have been invoked from the shell's path, 
* so we search $PATH for the named executable and use that. If the 
* executable was not found on $PATH (or there was no $PATH environment 
* variable), the original argv[0] string is used. 
* 
* Next, the executable location is examined to see if it is a symbolic 
* link. If so, the link is chased (correctly interpreting a relative 
* pathname if one is found) and the directory of the link target is used. 
* 
* Finally, argv0_path is set to the directory containing the executable 
* (i.e. the last component is stripped). 
* 
* With argv0_path in hand, we perform a number of steps. The same steps 
* are performed for prefix and for exec_prefix, but with a different 
* landmark. 
* 
* Step 1. Are we running python out of the build directory? This is 
* checked by looking for a different kind of landmark relative to 
* argv0_path. For prefix, the landmark's path is derived from the VPATH 
* preprocessor variable (taking into account that its value is almost, but 
* not quite, what we need). For exec_prefix, the landmark is 
* Modules/Setup. If the landmark is found, we're done. 
* 
* For the remaining steps, the prefix landmark will always be 
* lib/python$VERSION/os.py and the exec_prefix will always be 
* lib/python$VERSION/lib-dynload, where $VERSION is Python's version 
* number as supplied by the Makefile. Note that this means that no more 
* build directory checking is performed; if the first step did not find 
* the landmarks, the assumption is that python is running from an 
* installed setup. 
* 
* Step 2. See if the $PYTHONHOME environment variable points to the 
* installed location of the Python libraries. If $PYTHONHOME is set, then 
* it points to prefix and exec_prefix. $PYTHONHOME can be a single 
* directory, which is used for both, or the prefix and exec_prefix 
* directories separated by a colon. 
* 
* Step 3. Try to find prefix and exec_prefix relative to argv0_path, 
* backtracking up the path until it is exhausted. This is the most common 
* step to succeed. Note that if prefix and exec_prefix are different, 
* exec_prefix is more likely to be found; however if exec_prefix is a 
* subdirectory of prefix, both will be found. 
* 
* Step 4. Search the directories pointed to by the preprocessor variables 
* PREFIX and EXEC_PREFIX. These are supplied by the Makefile but can be 
* passed in as options to the configure script. 
* 
* That's it! 
* 
* Well, almost. Once we have determined prefix and exec_prefix, the 
* preprocessor variable PYTHONPATH is used to construct a path. Each 
* relative path on PYTHONPATH is prefixed with prefix. Then the directory 
* containing the shared library modules is appended. The environment 
* variable $PYTHONPATH is inserted in front of it all. Finally, the 
* prefix and exec_prefix globals are tweaked so they reflect the values 
* expected by other code, by stripping the "lib/python$VERSION/..." stuff 
* off. If either points to the build directory, the globals are reset to 
* the corresponding preprocessor variables (so sys.prefix will reflect the 
* installation location, even though sys.path points into the build 
* directory). This seems to make more sense given that currently the only 
* known use of sys.prefix and sys.exec_prefix is for the ILU installation 
* process to find the installed Python tree. 
*/ 

Answer 3

La mejor manera de resolver el problema de que la versión incorrecta se encuentra (por ejemplo 3.0 en lugar de 2.7) es para especificar la versión mínima para find_package (esto elegirá cualquier versión> = 2.7):

FIND_PACKAGE(PythonLibs 2.7 REQUIRED) 

o para obtener la versión exacta:

FIND_PACKAGE(PythonLibs 2.7.5 EXACT REQUIRED) 

Answer 4

Usted puede configurar manualmente en bibliotecas cmake \usr\share\cmake-3.2.3\Modules\FindPythonLibs.cmake:

set(PYTHON_LIBRARY "\\usr\\lib\\python2.7") 
set(PYTHON_INCLUDE_DIR "\\usr\\include\\python2.7")