Kaydet (Commit) 79e3d55b authored tarafından Georg Brandl's avatar Georg Brandl

Missed one big file to split up.

üst f6842722
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.. highlightlang:: c
.. _string-conversion:
String conversion and formatting
================================
Functions for number conversion and formatted string output.
.. cfunction:: int PyOS_snprintf(char *str, size_t size, const char *format, ...)
Output not more than *size* bytes to *str* according to the format string
*format* and the extra arguments. See the Unix man page :manpage:`snprintf(2)`.
.. cfunction:: int PyOS_vsnprintf(char *str, size_t size, const char *format, va_list va)
Output not more than *size* bytes to *str* according to the format string
*format* and the variable argument list *va*. Unix man page
:manpage:`vsnprintf(2)`.
:cfunc:`PyOS_snprintf` and :cfunc:`PyOS_vsnprintf` wrap the Standard C library
functions :cfunc:`snprintf` and :cfunc:`vsnprintf`. Their purpose is to
guarantee consistent behavior in corner cases, which the Standard C functions do
not.
The wrappers ensure that *str*[*size*-1] is always ``'\0'`` upon return. They
never write more than *size* bytes (including the trailing ``'\0'`` into str.
Both functions require that ``str != NULL``, ``size > 0`` and ``format !=
NULL``.
If the platform doesn't have :cfunc:`vsnprintf` and the buffer size needed to
avoid truncation exceeds *size* by more than 512 bytes, Python aborts with a
*Py_FatalError*.
The return value (*rv*) for these functions should be interpreted as follows:
* When ``0 <= rv < size``, the output conversion was successful and *rv*
characters were written to *str* (excluding the trailing ``'\0'`` byte at
*str*[*rv*]).
* When ``rv >= size``, the output conversion was truncated and a buffer with
``rv + 1`` bytes would have been needed to succeed. *str*[*size*-1] is ``'\0'``
in this case.
* When ``rv < 0``, "something bad happened." *str*[*size*-1] is ``'\0'`` in
this case too, but the rest of *str* is undefined. The exact cause of the error
depends on the underlying platform.
The following functions provide locale-independent string to number conversions.
.. cfunction:: double PyOS_ascii_strtod(const char *nptr, char **endptr)
Convert a string to a :ctype:`double`. This function behaves like the Standard C
function :cfunc:`strtod` does in the C locale. It does this without changing the
current locale, since that would not be thread-safe.
:cfunc:`PyOS_ascii_strtod` should typically be used for reading configuration
files or other non-user input that should be locale independent.
.. versionadded:: 2.4
See the Unix man page :manpage:`strtod(2)` for details.
.. cfunction:: char * PyOS_ascii_formatd(char *buffer, size_t buf_len, const char *format, double d)
Convert a :ctype:`double` to a string using the ``'.'`` as the decimal
separator. *format* is a :cfunc:`printf`\ -style format string specifying the
number format. Allowed conversion characters are ``'e'``, ``'E'``, ``'f'``,
``'F'``, ``'g'`` and ``'G'``.
The return value is a pointer to *buffer* with the converted string or NULL if
the conversion failed.
.. versionadded:: 2.4
.. cfunction:: double PyOS_ascii_atof(const char *nptr)
Convert a string to a :ctype:`double` in a locale-independent way.
.. versionadded:: 2.4
See the Unix man page :manpage:`atof(2)` for details.
.. cfunction:: char * PyOS_stricmp(char *s1, char *s2)
Case insensitive comparsion of strings. The functions works almost
identical to :cfunc:`strcmp` except that it ignores the case.
.. versionadded:: 2.6
.. cfunction:: char * PyOS_strnicmp(char *s1, char *s2, Py_ssize_t size)
Case insensitive comparsion of strings. The functions works almost
identical to :cfunc:`strncmp` except that it ignores the case.
.. versionadded:: 2.6
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.. highlightlang:: c
.. _marshalling-utils:
Data marshalling support
========================
These routines allow C code to work with serialized objects using the same data
format as the :mod:`marshal` module. There are functions to write data into the
serialization format, and additional functions that can be used to read the data
back. Files used to store marshalled data must be opened in binary mode.
Numeric values are stored with the least significant byte first.
The module supports two versions of the data format: version 0 is the historical
version, version 1 (new in Python 2.4) shares interned strings in the file, and
upon unmarshalling. *Py_MARSHAL_VERSION* indicates the current file format
(currently 1).
.. cfunction:: void PyMarshal_WriteLongToFile(long value, FILE *file, int version)
Marshal a :ctype:`long` integer, *value*, to *file*. This will only write the
least-significant 32 bits of *value*; regardless of the size of the native
:ctype:`long` type.
.. versionchanged:: 2.4
*version* indicates the file format.
.. cfunction:: void PyMarshal_WriteObjectToFile(PyObject *value, FILE *file, int version)
Marshal a Python object, *value*, to *file*.
.. versionchanged:: 2.4
*version* indicates the file format.
.. cfunction:: PyObject* PyMarshal_WriteObjectToString(PyObject *value, int version)
Return a string object containing the marshalled representation of *value*.
.. versionchanged:: 2.4
*version* indicates the file format.
The following functions allow marshalled values to be read back in.
XXX What about error detection? It appears that reading past the end of the
file will always result in a negative numeric value (where that's relevant), but
it's not clear that negative values won't be handled properly when there's no
error. What's the right way to tell? Should only non-negative values be written
using these routines?
.. cfunction:: long PyMarshal_ReadLongFromFile(FILE *file)
Return a C :ctype:`long` from the data stream in a :ctype:`FILE\*` opened for
reading. Only a 32-bit value can be read in using this function, regardless of
the native size of :ctype:`long`.
.. cfunction:: int PyMarshal_ReadShortFromFile(FILE *file)
Return a C :ctype:`short` from the data stream in a :ctype:`FILE\*` opened for
reading. Only a 16-bit value can be read in using this function, regardless of
the native size of :ctype:`short`.
.. cfunction:: PyObject* PyMarshal_ReadObjectFromFile(FILE *file)
Return a Python object from the data stream in a :ctype:`FILE\*` opened for
reading. On error, sets the appropriate exception (:exc:`EOFError` or
:exc:`TypeError`) and returns *NULL*.
.. cfunction:: PyObject* PyMarshal_ReadLastObjectFromFile(FILE *file)
Return a Python object from the data stream in a :ctype:`FILE\*` opened for
reading. Unlike :cfunc:`PyMarshal_ReadObjectFromFile`, this function assumes
that no further objects will be read from the file, allowing it to aggressively
load file data into memory so that the de-serialization can operate from data in
memory rather than reading a byte at a time from the file. Only use these
variant if you are certain that you won't be reading anything else from the
file. On error, sets the appropriate exception (:exc:`EOFError` or
:exc:`TypeError`) and returns *NULL*.
.. cfunction:: PyObject* PyMarshal_ReadObjectFromString(char *string, Py_ssize_t len)
Return a Python object from the data stream in a character buffer containing
*len* bytes pointed to by *string*. On error, sets the appropriate exception
(:exc:`EOFError` or :exc:`TypeError`) and returns *NULL*.
.. highlightlang:: c
.. _reflection:
Reflection
==========
.. cfunction:: PyObject* PyEval_GetBuiltins()
Return a dictionary of the builtins in the current execution frame,
or the interpreter of the thread state if no frame is currently executing.
.. cfunction:: PyObject* PyEval_GetLocals()
Return a dictionary of the local variables in the current execution frame,
or *NULL* if no frame is currently executing.
.. cfunction:: PyObject* PyEval_GetGlobals()
Return a dictionary of the global variables in the current execution frame,
or *NULL* if no frame is currently executing.
.. cfunction:: PyFrameObject* PyEval_GetFrame()
Return the current thread state's frame, which is *NULL* if no frame is
currently executing.
.. cfunction:: int PyEval_GetRestricted()
If there is a current frame and it is executing in restricted mode, return true,
otherwise false.
.. cfunction:: const char* PyEval_GetFuncName(PyObject *func)
Return the name of *func* if it is a function, class or instance object, else the
name of *func*\s type.
.. cfunction:: const char* PyEval_GetFuncDesc(PyObject *func)
Return a description string, depending on the type of *func*.
Return values include "()" for functions and methods, " constructor",
" instance", and " object". Concatenated with the result of
:cfunc:`PyEval_GetFuncName`, the result will be a description of
*func*.
.. highlightlang:: c
.. _os:
Operating System Utilities
==========================
.. cfunction:: int Py_FdIsInteractive(FILE *fp, const char *filename)
Return true (nonzero) if the standard I/O file *fp* with name *filename* is
deemed interactive. This is the case for files for which ``isatty(fileno(fp))``
is true. If the global flag :cdata:`Py_InteractiveFlag` is true, this function
also returns true if the *filename* pointer is *NULL* or if the name is equal to
one of the strings ``'<stdin>'`` or ``'???'``.
.. cfunction:: long PyOS_GetLastModificationTime(char *filename)
Return the time of last modification of the file *filename*. The result is
encoded in the same way as the timestamp returned by the standard C library
function :cfunc:`time`.
.. cfunction:: void PyOS_AfterFork()
Function to update some internal state after a process fork; this should be
called in the new process if the Python interpreter will continue to be used.
If a new executable is loaded into the new process, this function does not need
to be called.
.. cfunction:: int PyOS_CheckStack()
Return true when the interpreter runs out of stack space. This is a reliable
check, but is only available when :const:`USE_STACKCHECK` is defined (currently
on Windows using the Microsoft Visual C++ compiler). :const:`USE_STACKCHECK`
will be defined automatically; you should never change the definition in your
own code.
.. cfunction:: PyOS_sighandler_t PyOS_getsig(int i)
Return the current signal handler for signal *i*. This is a thin wrapper around
either :cfunc:`sigaction` or :cfunc:`signal`. Do not call those functions
directly! :ctype:`PyOS_sighandler_t` is a typedef alias for :ctype:`void
(\*)(int)`.
.. cfunction:: PyOS_sighandler_t PyOS_setsig(int i, PyOS_sighandler_t h)
Set the signal handler for signal *i* to be *h*; return the old signal handler.
This is a thin wrapper around either :cfunc:`sigaction` or :cfunc:`signal`. Do
not call those functions directly! :ctype:`PyOS_sighandler_t` is a typedef
alias for :ctype:`void (\*)(int)`.
.. _systemfunctions:
System Functions
================
These are utility functions that make functionality from the :mod:`sys` module
accessible to C code. They all work with the current interpreter thread's
:mod:`sys` module's dict, which is contained in the internal thread state structure.
.. cfunction:: PyObject *PySys_GetObject(char *name)
Return the object *name* from the :mod:`sys` module or *NULL* if it does
not exist, without setting an exception.
.. cfunction:: FILE *PySys_GetFile(char *name, FILE *def)
Return the :ctype:`FILE*` associated with the object *name* in the
:mod:`sys` module, or *def* if *name* is not in the module or is not associated
with a :ctype:`FILE*`.
.. cfunction:: int PySys_SetObject(char *name, PyObject *v)
Set *name* in the :mod:`sys` module to *v* unless *v* is *NULL*, in which
case *name* is deleted from the sys module. Returns ``0`` on success, ``-1``
on error.
.. cfunction:: void PySys_ResetWarnOptions(void)
Reset :data:`sys.warnoptions` to an empty list.
.. cfunction:: void PySys_AddWarnOption(char *s)
Append *s* to :data:`sys.warnoptions`.
.. cfunction:: void PySys_SetPath(char *path)
Set :data:`sys.path` to a list object of paths found in *path* which should
be a list of paths separated with the platform's search path delimiter
(``:`` on Unix, ``;`` on Windows).
.. cfunction:: void PySys_WriteStdout(const char *format, ...)
Write the output string described by *format* to :data:`sys.stdout`. No
exceptions are raised, even if truncation occurs (see below).
*format* should limit the total size of the formatted output string to
1000 bytes or less -- after 1000 bytes, the output string is truncated.
In particular, this means that no unrestricted "%s" formats should occur;
these should be limited using "%.<N>s" where <N> is a decimal number
calculated so that <N> plus the maximum size of other formatted text does not
exceed 1000 bytes. Also watch out for "%f", which can print hundreds of
digits for very large numbers.
If a problem occurs, or :data:`sys.stdout` is unset, the formatted message
is written to the real (C level) *stdout*.
.. cfunction:: void PySys_WriteStderr(const char *format, ...)
As above, but write to :data:`sys.stderr` or *stderr* instead.
.. _processcontrol:
Process Control
===============
.. cfunction:: void Py_FatalError(const char *message)
.. index:: single: abort()
Print a fatal error message and kill the process. No cleanup is performed.
This function should only be invoked when a condition is detected that would
make it dangerous to continue using the Python interpreter; e.g., when the
object administration appears to be corrupted. On Unix, the standard C library
function :cfunc:`abort` is called which will attempt to produce a :file:`core`
file.
.. cfunction:: void Py_Exit(int status)
.. index::
single: Py_Finalize()
single: exit()
Exit the current process. This calls :cfunc:`Py_Finalize` and then calls the
standard C library function ``exit(status)``.
.. cfunction:: int Py_AtExit(void (*func) ())
.. index::
single: Py_Finalize()
single: cleanup functions
Register a cleanup function to be called by :cfunc:`Py_Finalize`. The cleanup
function will be called with no arguments and should return no value. At most
32 cleanup functions can be registered. When the registration is successful,
:cfunc:`Py_AtExit` returns ``0``; on failure, it returns ``-1``. The cleanup
function registered last is called first. Each cleanup function will be called
at most once. Since Python's internal finalization will have completed before
the cleanup function, no Python APIs should be called by *func*.
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