/Doc/c-api/veryhigh.rst
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- .. highlightlang:: c
- .. _veryhigh:
- *************************
- The Very High Level Layer
- *************************
- The functions in this chapter will let you execute Python source code given in a
- file or a buffer, but they will not let you interact in a more detailed way with
- the interpreter.
- Several of these functions accept a start symbol from the grammar as a
- parameter. The available start symbols are :const:`Py_eval_input`,
- :const:`Py_file_input`, and :const:`Py_single_input`. These are described
- following the functions which accept them as parameters.
- Note also that several of these functions take :ctype:`FILE\*` parameters. One
- particular issue which needs to be handled carefully is that the :ctype:`FILE`
- structure for different C libraries can be different and incompatible. Under
- Windows (at least), it is possible for dynamically linked extensions to actually
- use different libraries, so care should be taken that :ctype:`FILE\*` parameters
- are only passed to these functions if it is certain that they were created by
- the same library that the Python runtime is using.
- .. cfunction:: int Py_Main(int argc, char **argv)
- The main program for the standard interpreter. This is made available for
- programs which embed Python. The *argc* and *argv* parameters should be
- prepared exactly as those which are passed to a C program's :cfunc:`main`
- function. It is important to note that the argument list may be modified (but
- the contents of the strings pointed to by the argument list are not). The return
- value will be the integer passed to the :func:`sys.exit` function, ``1`` if the
- interpreter exits due to an exception, or ``2`` if the parameter list does not
- represent a valid Python command line.
- Note that if an otherwise unhandled :exc:`SystemError` is raised, this
- function will not return ``1``, but exit the process, as long as
- ``Py_InspectFlag`` is not set.
- .. cfunction:: int PyRun_AnyFile(FILE *fp, const char *filename)
- This is a simplified interface to :cfunc:`PyRun_AnyFileExFlags` below, leaving
- *closeit* set to ``0`` and *flags* set to *NULL*.
- .. cfunction:: int PyRun_AnyFileFlags(FILE *fp, const char *filename, PyCompilerFlags *flags)
- This is a simplified interface to :cfunc:`PyRun_AnyFileExFlags` below, leaving
- the *closeit* argument set to ``0``.
- .. cfunction:: int PyRun_AnyFileEx(FILE *fp, const char *filename, int closeit)
- This is a simplified interface to :cfunc:`PyRun_AnyFileExFlags` below, leaving
- the *flags* argument set to *NULL*.
- .. cfunction:: int PyRun_AnyFileExFlags(FILE *fp, const char *filename, int closeit, PyCompilerFlags *flags)
- If *fp* refers to a file associated with an interactive device (console or
- terminal input or Unix pseudo-terminal), return the value of
- :cfunc:`PyRun_InteractiveLoop`, otherwise return the result of
- :cfunc:`PyRun_SimpleFile`. If *filename* is *NULL*, this function uses
- ``"???"`` as the filename.
- .. cfunction:: int PyRun_SimpleString(const char *command)
- This is a simplified interface to :cfunc:`PyRun_SimpleStringFlags` below,
- leaving the *PyCompilerFlags\** argument set to NULL.
- .. cfunction:: int PyRun_SimpleStringFlags(const char *command, PyCompilerFlags *flags)
- Executes the Python source code from *command* in the :mod:`__main__` module
- according to the *flags* argument. If :mod:`__main__` does not already exist, it
- is created. Returns ``0`` on success or ``-1`` if an exception was raised. If
- there was an error, there is no way to get the exception information. For the
- meaning of *flags*, see below.
- Note that if an otherwise unhandled :exc:`SystemError` is raised, this
- function will not return ``-1``, but exit the process, as long as
- ``Py_InspectFlag`` is not set.
- .. cfunction:: int PyRun_SimpleFile(FILE *fp, const char *filename)
- This is a simplified interface to :cfunc:`PyRun_SimpleFileExFlags` below,
- leaving *closeit* set to ``0`` and *flags* set to *NULL*.
- .. cfunction:: int PyRun_SimpleFileFlags(FILE *fp, const char *filename, PyCompilerFlags *flags)
- This is a simplified interface to :cfunc:`PyRun_SimpleFileExFlags` below,
- leaving *closeit* set to ``0``.
- .. cfunction:: int PyRun_SimpleFileEx(FILE *fp, const char *filename, int closeit)
- This is a simplified interface to :cfunc:`PyRun_SimpleFileExFlags` below,
- leaving *flags* set to *NULL*.
- .. cfunction:: int PyRun_SimpleFileExFlags(FILE *fp, const char *filename, int closeit, PyCompilerFlags *flags)
- Similar to :cfunc:`PyRun_SimpleStringFlags`, but the Python source code is read
- from *fp* instead of an in-memory string. *filename* should be the name of the
- file. If *closeit* is true, the file is closed before PyRun_SimpleFileExFlags
- returns.
- .. cfunction:: int PyRun_InteractiveOne(FILE *fp, const char *filename)
- This is a simplified interface to :cfunc:`PyRun_InteractiveOneFlags` below,
- leaving *flags* set to *NULL*.
- .. cfunction:: int PyRun_InteractiveOneFlags(FILE *fp, const char *filename, PyCompilerFlags *flags)
- Read and execute a single statement from a file associated with an interactive
- device according to the *flags* argument. If *filename* is *NULL*, ``"???"`` is
- used instead. The user will be prompted using ``sys.ps1`` and ``sys.ps2``.
- Returns ``0`` when the input was executed successfully, ``-1`` if there was an
- exception, or an error code from the :file:`errcode.h` include file distributed
- as part of Python if there was a parse error. (Note that :file:`errcode.h` is
- not included by :file:`Python.h`, so must be included specifically if needed.)
- .. cfunction:: int PyRun_InteractiveLoop(FILE *fp, const char *filename)
- This is a simplified interface to :cfunc:`PyRun_InteractiveLoopFlags` below,
- leaving *flags* set to *NULL*.
- .. cfunction:: int PyRun_InteractiveLoopFlags(FILE *fp, const char *filename, PyCompilerFlags *flags)
- Read and execute statements from a file associated with an interactive device
- until EOF is reached. If *filename* is *NULL*, ``"???"`` is used instead. The
- user will be prompted using ``sys.ps1`` and ``sys.ps2``. Returns ``0`` at EOF.
- .. cfunction:: struct _node* PyParser_SimpleParseString(const char *str, int start)
- This is a simplified interface to
- :cfunc:`PyParser_SimpleParseStringFlagsFilename` below, leaving *filename* set
- to *NULL* and *flags* set to ``0``.
- .. cfunction:: struct _node* PyParser_SimpleParseStringFlags( const char *str, int start, int flags)
- This is a simplified interface to
- :cfunc:`PyParser_SimpleParseStringFlagsFilename` below, leaving *filename* set
- to *NULL*.
- .. cfunction:: struct _node* PyParser_SimpleParseStringFlagsFilename( const char *str, const char *filename, int start, int flags)
- Parse Python source code from *str* using the start token *start* according to
- the *flags* argument. The result can be used to create a code object which can
- be evaluated efficiently. This is useful if a code fragment must be evaluated
- many times.
- .. cfunction:: struct _node* PyParser_SimpleParseFile(FILE *fp, const char *filename, int start)
- This is a simplified interface to :cfunc:`PyParser_SimpleParseFileFlags` below,
- leaving *flags* set to ``0``
- .. cfunction:: struct _node* PyParser_SimpleParseFileFlags(FILE *fp, const char *filename, int start, int flags)
- Similar to :cfunc:`PyParser_SimpleParseStringFlagsFilename`, but the Python
- source code is read from *fp* instead of an in-memory string.
- .. cfunction:: PyObject* PyRun_String(const char *str, int start, PyObject *globals, PyObject *locals)
- This is a simplified interface to :cfunc:`PyRun_StringFlags` below, leaving
- *flags* set to *NULL*.
- .. cfunction:: PyObject* PyRun_StringFlags(const char *str, int start, PyObject *globals, PyObject *locals, PyCompilerFlags *flags)
- Execute Python source code from *str* in the context specified by the
- dictionaries *globals* and *locals* with the compiler flags specified by
- *flags*. The parameter *start* specifies the start token that should be used to
- parse the source code.
- Returns the result of executing the code as a Python object, or *NULL* if an
- exception was raised.
- .. cfunction:: PyObject* PyRun_File(FILE *fp, const char *filename, int start, PyObject *globals, PyObject *locals)
- This is a simplified interface to :cfunc:`PyRun_FileExFlags` below, leaving
- *closeit* set to ``0`` and *flags* set to *NULL*.
- .. cfunction:: PyObject* PyRun_FileEx(FILE *fp, const char *filename, int start, PyObject *globals, PyObject *locals, int closeit)
- This is a simplified interface to :cfunc:`PyRun_FileExFlags` below, leaving
- *flags* set to *NULL*.
- .. cfunction:: PyObject* PyRun_FileFlags(FILE *fp, const char *filename, int start, PyObject *globals, PyObject *locals, PyCompilerFlags *flags)
- This is a simplified interface to :cfunc:`PyRun_FileExFlags` below, leaving
- *closeit* set to ``0``.
- .. cfunction:: PyObject* PyRun_FileExFlags(FILE *fp, const char *filename, int start, PyObject *globals, PyObject *locals, int closeit, PyCompilerFlags *flags)
- Similar to :cfunc:`PyRun_StringFlags`, but the Python source code is read from
- *fp* instead of an in-memory string. *filename* should be the name of the file.
- If *closeit* is true, the file is closed before :cfunc:`PyRun_FileExFlags`
- returns.
- .. cfunction:: PyObject* Py_CompileString(const char *str, const char *filename, int start)
- This is a simplified interface to :cfunc:`Py_CompileStringFlags` below, leaving
- *flags* set to *NULL*.
- .. cfunction:: PyObject* Py_CompileStringFlags(const char *str, const char *filename, int start, PyCompilerFlags *flags)
- Parse and compile the Python source code in *str*, returning the resulting code
- object. The start token is given by *start*; this can be used to constrain the
- code which can be compiled and should be :const:`Py_eval_input`,
- :const:`Py_file_input`, or :const:`Py_single_input`. The filename specified by
- *filename* is used to construct the code object and may appear in tracebacks or
- :exc:`SyntaxError` exception messages. This returns *NULL* if the code cannot
- be parsed or compiled.
- .. cfunction:: PyObject* PyEval_EvalCode(PyCodeObject *co, PyObject *globals, PyObject *locals)
- This is a simplified interface to :cfunc:`PyEval_EvalCodeEx`, with just
- the code object, and the dictionaries of global and local variables.
- The other arguments are set to *NULL*.
- .. cfunction:: PyObject* PyEval_EvalCodeEx(PyCodeObject *co, PyObject *globals, PyObject *locals, PyObject **args, int argcount, PyObject **kws, int kwcount, PyObject **defs, int defcount, PyObject *closure)
- Evaluate a precompiled code object, given a particular environment for its
- evaluation. This environment consists of dictionaries of global and local
- variables, arrays of arguments, keywords and defaults, and a closure tuple of
- cells.
- .. cfunction:: PyObject* PyEval_EvalFrame(PyFrameObject *f)
- Evaluate an execution frame. This is a simplified interface to
- PyEval_EvalFrameEx, for backward compatibility.
- .. cfunction:: PyObject* PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
- This is the main, unvarnished function of Python interpretation. It is
- literally 2000 lines long. The code object associated with the execution
- frame *f* is executed, interpreting bytecode and executing calls as needed.
- The additional *throwflag* parameter can mostly be ignored - if true, then
- it causes an exception to immediately be thrown; this is used for the
- :meth:`throw` methods of generator objects.
- .. cfunction:: int PyEval_MergeCompilerFlags(PyCompilerFlags *cf)
- This function changes the flags of the current evaluation frame, and returns
- true on success, false on failure.
- .. cvar:: int Py_eval_input
- .. index:: single: Py_CompileString()
- The start symbol from the Python grammar for isolated expressions; for use with
- :cfunc:`Py_CompileString`.
- .. cvar:: int Py_file_input
- .. index:: single: Py_CompileString()
- The start symbol from the Python grammar for sequences of statements as read
- from a file or other source; for use with :cfunc:`Py_CompileString`. This is
- the symbol to use when compiling arbitrarily long Python source code.
- .. cvar:: int Py_single_input
- .. index:: single: Py_CompileString()
- The start symbol from the Python grammar for a single statement; for use with
- :cfunc:`Py_CompileString`. This is the symbol used for the interactive
- interpreter loop.
- .. ctype:: struct PyCompilerFlags
- This is the structure used to hold compiler flags. In cases where code is only
- being compiled, it is passed as ``int flags``, and in cases where code is being
- executed, it is passed as ``PyCompilerFlags *flags``. In this case, ``from
- __future__ import`` can modify *flags*.
- Whenever ``PyCompilerFlags *flags`` is *NULL*, :attr:`cf_flags` is treated as
- equal to ``0``, and any modification due to ``from __future__ import`` is
- discarded. ::
- struct PyCompilerFlags {
- int cf_flags;
- }
- .. cvar:: int CO_FUTURE_DIVISION
- This bit can be set in *flags* to cause division operator ``/`` to be
- interpreted as "true division" according to :pep:`238`.