Data marshalling support
************************

These routines allow C code to work with serialized objects using the
same data format as the "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 several versions of the data format; see the
"Python module documentation" for details.

The following exceptions can be raised by these functions:
"ValueError" if the value cannot be marshalled, "ValueError" or
"TypeError" if the data is malformed, "EOFError" if the end of the
data is reached before the value is complete, "OSError" if reading
from or writing to a FILE* fails, "KeyboardInterrupt" if reading or
writing is interrupted by a signal, and "MemoryError" if memory
allocation fails.

Geändert in Version 3.16: Previously, in functions taking a FILE*, the
reading functions raised "EOFError" instead of "OSError" and
"KeyboardInterrupt", and the writing functions ignored I/O errors and
interruptions.

Py_MARSHAL_VERSION

   The current format version. See "marshal.version".

void PyMarshal_WriteLongToFile(long value, FILE *file, int version)

   Marshal a long integer, *value*, to *file*.  This will only write
   the least-significant 32 bits of *value*; regardless of the size of
   the native long type.  *version* indicates the file format.

   This function can fail, in which case it sets the error indicator.
   Use "PyErr_Occurred()" to check for that.

   Bemerkung:

     In Python 3.15 and earlier, this function does not set the error
     indicator if writing to *file* fails. The same caveat applies as
     for "PyMarshal_WriteObjectToFile()".

void PyMarshal_WriteObjectToFile(PyObject *value, FILE *file, int version)

   Marshal a Python object, *value*, to *file*. *version* indicates
   the file format.

   The marshalled representation of *value* is built in memory and
   then written to *file*. Nothing is written if *value* cannot be
   marshalled.

   This function can fail, in which case it sets the error indicator.
   Use "PyErr_Occurred()" to check for that.

   Bemerkung:

     In Python 3.15 and earlier, this function can write only part of
     the data to *file* and return without setting the error
     indicator, for example if *value* contains an object which cannot
     be marshalled or if writing to *file* fails (see gh-155907). Code
     which has to support these versions cannot rely on
     "PyErr_Occurred()" alone to know that all the data was written.
     It can use "PyMarshal_WriteObjectToString()" and write the result
     itself, or validate what was written.

   Geändert in Version 3.16: Previously, the data was written to
   *file* as it was produced, using a buffer of constant size, and
   incomplete data was written if *value* could not be marshalled.

PyObject *PyMarshal_WriteObjectToString(PyObject *value, int version)
    *Rückgabewert: neue Referenz.*

   Return a bytes object containing the marshalled representation of
   *value*. *version* indicates the file format.

   On error, raises an exception and returns "NULL".

The following functions allow marshalled values to be read back in.

long PyMarshal_ReadLongFromFile(FILE *file)

   Return a C long from the data stream in a FILE* opened for reading.
   Only a 32-bit value can be read in using this function, regardless
   of the native size of long.

   On error, raises an exception and returns "-1".

int PyMarshal_ReadShortFromFile(FILE *file)

   Return a C short from the data stream in a FILE* opened for
   reading.  Only a 16-bit value can be read in using this function,
   regardless of the native size of short.

   On error, raises an exception and returns "-1".

PyObject *PyMarshal_ReadObjectFromFile(FILE *file)
    *Rückgabewert: neue Referenz.*

   Return a Python object from the data stream in a FILE* opened for
   reading.

   On error, raises an exception and returns "NULL".

PyObject *PyMarshal_ReadLastObjectFromFile(FILE *file)
    *Rückgabewert: neue Referenz.*

   Return a Python object from the data stream in a FILE* opened for
   reading.  Unlike "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 this variant if
   you are certain that you won't be reading anything else from the
   file.

   On error, raises an exception and returns "NULL".

PyObject *PyMarshal_ReadObjectFromString(const char *data, Py_ssize_t len)
    *Rückgabewert: neue Referenz.*

   Return a Python object from the data stream in a byte buffer
   containing *len* bytes pointed to by *data*.

   On error, raises an exception and returns "NULL".
