FM / numpy

/usr/lib64/python2.6/site-packages/numpy/core/include/numpy/

/usr/lib64/python2.6/site-packages/numpy/core/include/numpy

Name	Size	Mode	Actions
arrayobject.h	508	0644	edit dl rm
arrayscalars.h	3149	0644	edit dl rm
multiarray_api.txt	26406	0644	edit dl rm
ndarrayobject.h	60660	0644	edit dl rm
noprefix.h	6458	0644	edit dl rm
npy_common.h	30614	0644	edit dl rm
npy_cpu.h	3460	0644	edit dl rm
npy_endian.h	1315	0644	edit dl rm
npy_interrupt.h	3411	0644	edit dl rm
npy_math.h	13001	0644	edit dl rm
npy_os.h	817	0644	edit dl rm
numpyconfig.h	508	0644	edit dl rm
oldnumeric.h	684	0644	edit dl rm
old_defines.h	5937	0644	edit dl rm
ufuncobject.h	12978	0644	edit dl rm
ufunc_api.txt	3941	0644	edit dl rm
utils.h	628	0644	edit dl rm
_neighborhood_iterator_imp.h	1861	0644	edit dl rm
_numpyconfig.h	883	0644	edit dl rm
__multiarray_api.h	46130	0644	edit dl rm
__ufunc_api.h	8450	0644	edit dl rm

Edit: /usr/lib64/python2.6/site-packages/numpy/core/include/numpy/npy_interrupt.h (3411B)

/* Signal handling:

This header file defines macros that allow your code to handle
interrupts received during processing.  Interrupts that
could reasonably be handled:

SIGINT, SIGABRT, SIGALRM, SIGSEGV

****Warning***************

Do not allow code that creates temporary memory or increases reference
counts of Python objects to be interrupted unless you handle it
differently.

**************************

The mechanism for handling interrupts is conceptually simple:

- replace the signal handler with our own home-grown version
     and store the old one.
  - run the code to be interrupted -- if an interrupt occurs
     the handler should basically just cause a return to the
     calling function for finish work.
  - restore the old signal handler

Of course, every code that allows interrupts must account for
returning via the interrupt and handle clean-up correctly.  But,
even still, the simple paradigm is complicated by at least three
factors.

1) platform portability (i.e. Microsoft says not to use longjmp
     to return from signal handling.  They have a __try  and __except
     extension to C instead but what about mingw?).

2) how to handle threads: apparently whether signals are delivered to
    every thread of the process or the "invoking" thread is platform
    dependent. --- we don't handle threads for now.

3) do we need to worry about re-entrance.  For now, assume the
    code will not call-back into itself.

Ideas:

1) Start by implementing an approach that works on platforms that
    can use setjmp and longjmp functionality and does nothing
    on other platforms.

2) Ignore threads --- i.e. do not mix interrupt handling and threads

3) Add a default signal_handler function to the C-API but have the rest
    use macros.

Simple Interface:

In your C-extension: around a block of code you want to be interruptable
with a SIGINT

NPY_SIGINT_ON
[code]
NPY_SIGINT_OFF

In order for this to work correctly, the
[code] block must not allocate any memory or alter the reference count of any
Python objects.  In other words [code] must be interruptible so that continuation
after NPY_SIGINT_OFF will only be "missing some computations"

Interrupt handling does not work well with threads.

/* Add signal handling macros
   Make the global variable and signal handler part of the C-API
*/

#ifndef NPY_INTERRUPT_H
#define NPY_INTERRUPT_H

#ifndef NPY_NO_SIGNAL

#include <setjmp.h>
#include <signal.h>

#ifndef sigsetjmp

#define SIGSETJMP(arg1, arg2) setjmp(arg1)
#define SIGLONGJMP(arg1, arg2) longjmp(arg1, arg2)
#define SIGJMP_BUF jmp_buf

#else

#define SIGSETJMP(arg1, arg2) sigsetjmp(arg1, arg2)
#define SIGLONGJMP(arg1, arg2) siglongjmp(arg1, arg2)
#define SIGJMP_BUF sigjmp_buf

#endif

#    define NPY_SIGINT_ON {                                             \
                   PyOS_sighandler_t _npy_sig_save;                     \
                   _npy_sig_save = PyOS_setsig(SIGINT, _PyArray_SigintHandler); \
                   if (SIGSETJMP(*((SIGJMP_BUF *)_PyArray_GetSigintBuf()), \
                                 1) == 0) {                             \

#    define NPY_SIGINT_OFF }                                      \
        PyOS_setsig(SIGINT, _npy_sig_save);                       \
        }

#else /* NPY_NO_SIGNAL  */

#  define NPY_SIGINT_ON
#  define NPY_SIGINT_OFF

#endif /* HAVE_SIGSETJMP */

#endif /* NPY_INTERRUPT_H */

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