"""Unit tests for contextlib.py, and other context managers."""
import sys
import tempfile
import unittest
from contextlib import * # Tests __all__
from test import support
try:
import threading
except ImportError:
threading = None
class ContextManagerTestCase(unittest.TestCase):
def test_contextmanager_plain(self):
state = []
@contextmanager
def woohoo():
state.append(1)
yield 42
state.append(999)
with woohoo() as x:
self.assertEqual(state, [1])
self.assertEqual(x, 42)
state.append(x)
self.assertEqual(state, [1, 42, 999])
def test_contextmanager_finally(self):
state = []
@contextmanager
def woohoo():
state.append(1)
try:
yield 42
finally:
state.append(999)
with self.assertRaises(ZeroDivisionError):
with woohoo() as x:
self.assertEqual(state, [1])
self.assertEqual(x, 42)
state.append(x)
raise ZeroDivisionError()
self.assertEqual(state, [1, 42, 999])
def test_contextmanager_no_reraise(self):
@contextmanager
def whee():
yield
ctx = whee()
ctx.__enter__()
# Calling __exit__ should not result in an exception
self.assertFalse(ctx.__exit__(TypeError, TypeError("foo"), None))
def test_contextmanager_trap_yield_after_throw(self):
@contextmanager
def whoo():
try:
yield
except:
yield
ctx = whoo()
ctx.__enter__()
self.assertRaises(
RuntimeError, ctx.__exit__, TypeError, TypeError("foo"), None
)
def test_contextmanager_except(self):
state = []
@contextmanager
def woohoo():
state.append(1)
try:
yield 42
except ZeroDivisionError as e:
state.append(e.args[0])
self.assertEqual(state, [1, 42, 999])
with woohoo() as x:
self.assertEqual(state, [1])
self.assertEqual(x, 42)
state.append(x)
raise ZeroDivisionError(999)
self.assertEqual(state, [1, 42, 999])
def _create_contextmanager_attribs(self):
def attribs(**kw):
def decorate(func):
for k,v in kw.items():
setattr(func,k,v)
return func
return decorate
@contextmanager
@attribs(foo='bar')
def baz(spam):
"""Whee!"""
return baz
def test_contextmanager_attribs(self):
baz = self._create_contextmanager_attribs()
self.assertEqual(baz.__name__,'baz')
self.assertEqual(baz.foo, 'bar')
@unittest.skipIf(sys.flags.optimize >= 2,
"Docstrings are omitted with -O2 and above")
def test_contextmanager_doc_attrib(self):
baz = self._create_contextmanager_attribs()
self.assertEqual(baz.__doc__, "Whee!")
class ClosingTestCase(unittest.TestCase):
# XXX This needs more work
def test_closing(self):
state = []
class C:
def close(self):
state.append(1)
x = C()
self.assertEqual(state, [])
with closing(x) as y:
self.assertEqual(x, y)
self.assertEqual(state, [1])
def test_closing_error(self):
state = []
class C:
def close(self):
state.append(1)
x = C()
self.assertEqual(state, [])
with self.assertRaises(ZeroDivisionError):
with closing(x) as y:
self.assertEqual(x, y)
1 / 0
self.assertEqual(state, [1])
class FileContextTestCase(unittest.TestCase):
def testWithOpen(self):
tfn = tempfile.mktemp()
try:
f = None
with open(tfn, "w") as f:
self.assertFalse(f.closed)
f.write("Booh\n")
self.assertTrue(f.closed)
f = None
with self.assertRaises(ZeroDivisionError):
with open(tfn, "r") as f:
self.assertFalse(f.closed)
self.assertEqual(f.read(), "Booh\n")
1 / 0
self.assertTrue(f.closed)
finally:
support.unlink(tfn)
@unittest.skipUnless(threading, 'Threading required for this test.')
class LockContextTestCase(unittest.TestCase):
def boilerPlate(self, lock, locked):
self.assertFalse(locked())
with lock:
self.assertTrue(locked())
self.assertFalse(locked())
with self.assertRaises(ZeroDivisionError):
with lock:
self.assertTrue(locked())
1 / 0
self.assertFalse(locked())
def testWithLock(self):
lock = threading.Lock()
self.boilerPlate(lock, lock.locked)
def testWithRLock(self):
lock = threading.RLock()
self.boilerPlate(lock, lock._is_owned)
def testWithCondition(self):
lock = threading.Condition()
def locked():
return lock._is_owned()
self.boilerPlate(lock, locked)
def testWithSemaphore(self):
lock = threading.Semaphore()
def locked():
if lock.acquire(False):
lock.release()
return False
else:
return True
self.boilerPlate(lock, locked)
def testWithBoundedSemaphore(self):
lock = threading.BoundedSemaphore()
def locked():
if lock.acquire(False):
lock.release()
return False
else:
return True
self.boilerPlate(lock, locked)
class mycontext(ContextDecorator):
started = False
exc = None
catch = False
def __enter__(self):
self.started = True
return self
def __exit__(self, *exc):
self.exc = exc
return self.catch
class TestContextDecorator(unittest.TestCase):
def test_contextdecorator(self):
context = mycontext()
with context as result:
self.assertIs(result, context)
self.assertTrue(context.started)
self.assertEqual(context.exc, (None, None, None))
def test_contextdecorator_with_exception(self):
context = mycontext()
with self.assertRaisesRegex(NameError, 'foo'):
with context:
raise NameError('foo')
self.assertIsNotNone(context.exc)
self.assertIs(context.exc[0], NameError)
context = mycontext()
context.catch = True
with context:
raise NameError('foo')
self.assertIsNotNone(context.exc)
self.assertIs(context.exc[0], NameError)
def test_decorator(self):
context = mycontext()
@context
def test():
self.assertIsNone(context.exc)
self.assertTrue(context.started)
test()
self.assertEqual(context.exc, (None, None, None))
def test_decorator_with_exception(self):
context = mycontext()
@context
def test():
self.assertIsNone(context.exc)
self.assertTrue(context.started)
raise NameError('foo')
with self.assertRaisesRegex(NameError, 'foo'):
test()
self.assertIsNotNone(context.exc)
self.assertIs(context.exc[0], NameError)
def test_decorating_method(self):
context = mycontext()
class Test(object):
@context
def method(self, a, b, c=None):
self.a = a
self.b = b
self.c = c
# these tests are for argument passing when used as a decorator
test = Test()
test.method(1, 2)
self.assertEqual(test.a, 1)
self.assertEqual(test.b, 2)
self.assertEqual(test.c, None)
test = Test()
test.method('a', 'b', 'c')
self.assertEqual(test.a, 'a')
self.assertEqual(test.b, 'b')
self.assertEqual(test.c, 'c')
test = Test()
test.method(a=1, b=2)
self.assertEqual(test.a, 1)
self.assertEqual(test.b, 2)
def test_typo_enter(self):
class mycontext(ContextDecorator):
def __unter__(self):
pass
def __exit__(self, *exc):
pass
with self.assertRaises(AttributeError):
with mycontext():
pass
def test_typo_exit(self):
class mycontext(ContextDecorator):
def __enter__(self):
pass
def __uxit__(self, *exc):
pass
with self.assertRaises(AttributeError):
with mycontext():
pass
def test_contextdecorator_as_mixin(self):
class somecontext(object):
started = False
exc = None
def __enter__(self):
self.started = True
return self
def __exit__(self, *exc):
self.exc = exc
class mycontext(somecontext, ContextDecorator):
pass
context = mycontext()
@context
def test():
self.assertIsNone(context.exc)
self.assertTrue(context.started)
test()
self.assertEqual(context.exc, (None, None, None))
def test_contextmanager_as_decorator(self):
@contextmanager
def woohoo(y):
state.append(y)
yield
state.append(999)
state = []
@woohoo(1)
def test(x):
self.assertEqual(state, [1])
state.append(x)
test('something')
self.assertEqual(state, [1, 'something', 999])
# Issue #11647: Ensure the decorated function is 'reusable'
state = []
test('something else')
self.assertEqual(state, [1, 'something else', 999])
class TestExitStack(unittest.TestCase):
def test_no_resources(self):
with ExitStack():
pass
def test_callback(self):
expected = [
((), {}),
((1,), {}),
((1,2), {}),
((), dict(example=1)),
((1,), dict(example=1)),
((1,2), dict(example=1)),
]
result = []
def _exit(*args, **kwds):
"""Test metadata propagation"""
result.append((args, kwds))
with ExitStack() as stack:
for args, kwds in reversed(expected):
if args and kwds:
f = stack.callback(_exit, *args, **kwds)
elif args:
f = stack.callback(_exit, *args)
elif kwds:
f = stack.callback(_exit, **kwds)
else:
f = stack.callback(_exit)
self.assertIs(f, _exit)
for wrapper in stack._exit_callbacks:
self.assertIs(wrapper.__wrapped__, _exit)
self.assertNotEqual(wrapper.__name__, _exit.__name__)
self.assertIsNone(wrapper.__doc__, _exit.__doc__)
self.assertEqual(result, expected)
def test_push(self):
exc_raised = ZeroDivisionError
def _expect_exc(exc_type, exc, exc_tb):
self.assertIs(exc_type, exc_raised)
def _suppress_exc(*exc_details):
return True
def _expect_ok(exc_type, exc, exc_tb):
self.assertIsNone(exc_type)
self.assertIsNone(exc)
self.assertIsNone(exc_tb)
class ExitCM(object):
def __init__(self, check_exc):
self.check_exc = check_exc
def __enter__(self):
self.fail("Should not be called!")
def __exit__(self, *exc_details):
self.check_exc(*exc_details)
with ExitStack() as stack:
stack.push(_expect_ok)
self.assertIs(stack._exit_callbacks[-1], _expect_ok)
cm = ExitCM(_expect_ok)
stack.push(cm)
self.assertIs(stack._exit_callbacks[-1].__self__, cm)
stack.push(_suppress_exc)
self.assertIs(stack._exit_callbacks[-1], _suppress_exc)
cm = ExitCM(_expect_exc)
stack.push(cm)
self.assertIs(stack._exit_callbacks[-1].__self__, cm)
stack.push(_expect_exc)
self.assertIs(stack._exit_callbacks[-1], _expect_exc)
stack.push(_expect_exc)
self.assertIs(stack._exit_callbacks[-1], _expect_exc)
1/0
def test_enter_context(self):
class TestCM(object):
def __enter__(self):
result.append(1)
def __exit__(self, *exc_details):
result.append(3)
result = []
cm = TestCM()
with ExitStack() as stack:
@stack.callback # Registered first => cleaned up last
def _exit():
result.append(4)
self.assertIsNotNone(_exit)
stack.enter_context(cm)
self.assertIs(stack._exit_callbacks[-1].__self__, cm)
result.append(2)
self.assertEqual(result, [1, 2, 3, 4])
def test_close(self):
result = []
with ExitStack() as stack:
@stack.callback
def _exit():
result.append(1)
self.assertIsNotNone(_exit)
stack.close()
result.append(2)
self.assertEqual(result, [1, 2])
def test_pop_all(self):
result = []
with ExitStack() as stack:
@stack.callback
def _exit():
result.append(3)
self.assertIsNotNone(_exit)
new_stack = stack.pop_all()
result.append(1)
result.append(2)
new_stack.close()
self.assertEqual(result, [1, 2, 3])
def test_exit_raise(self):
with self.assertRaises(ZeroDivisionError):
with ExitStack() as stack:
stack.push(lambda *exc: False)
1/0
def test_exit_suppress(self):
with ExitStack() as stack:
stack.push(lambda *exc: True)
1/0
def test_exit_exception_chaining_reference(self):
# Sanity check to make sure that ExitStack chaining matches
# actual nested with statements
class RaiseExc:
def __init__(self, exc):
self.exc = exc
def __enter__(self):
return self
def __exit__(self, *exc_details):
raise self.exc
class RaiseExcWithContext:
def __init__(self, outer, inner):
self.outer = outer
self.inner = inner
def __enter__(self):
return self
def __exit__(self, *exc_details):
try:
raise self.inner
except:
raise self.outer
class SuppressExc:
def __enter__(self):
return self
def __exit__(self, *exc_details):
type(self).saved_details = exc_details
return True
try:
with RaiseExc(IndexError):
with RaiseExcWithContext(KeyError, AttributeError):
with SuppressExc():
with RaiseExc(ValueError):
1 / 0
except IndexError as exc:
self.assertIsInstance(exc.__context__, KeyError)
self.assertIsInstance(exc.__context__.__context__, AttributeError)
# Inner exceptions were suppressed
self.assertIsNone(exc.__context__.__context__.__context__)
else:
self.fail("Expected IndexError, but no exception was raised")
# Check the inner exceptions
inner_exc = SuppressExc.saved_details[1]
self.assertIsInstance(inner_exc, ValueError)
self.assertIsInstance(inner_exc.__context__, ZeroDivisionError)
def test_exit_exception_chaining(self):
# Ensure exception chaining matches the reference behaviour
def raise_exc(exc):
raise exc
saved_details = None
def suppress_exc(*exc_details):
nonlocal saved_details
saved_details = exc_details
return True
try:
with ExitStack() as stack:
stack.callback(raise_exc, IndexError)
stack.callback(raise_exc, KeyError)
stack.callback(raise_exc, AttributeError)
stack.push(suppress_exc)
stack.callback(raise_exc, ValueError)
1 / 0
except IndexError as exc:
self.assertIsInstance(exc.__context__, KeyError)
self.assertIsInstance(exc.__context__.__context__, AttributeError)
# Inner exceptions were suppressed
self.assertIsNone(exc.__context__.__context__.__context__)
else:
self.fail("Expected IndexError, but no exception was raised")
# Check the inner exceptions
inner_exc = saved_details[1]
self.assertIsInstance(inner_exc, ValueError)
self.assertIsInstance(inner_exc.__context__, ZeroDivisionError)
def test_exit_exception_non_suppressing(self):
# http://bugs.python.org/issue19092
def raise_exc(exc):
raise exc
def suppress_exc(*exc_details):
return True
try:
with ExitStack() as stack:
stack.callback(lambda: None)
stack.callback(raise_exc, IndexError)
except Exception as exc:
self.assertIsInstance(exc, IndexError)
else:
self.fail("Expected IndexError, but no exception was raised")
try:
with ExitStack() as stack:
stack.callback(raise_exc, KeyError)
stack.push(suppress_exc)
stack.callback(raise_exc, IndexError)
except Exception as exc:
self.assertIsInstance(exc, KeyError)
else:
self.fail("Expected KeyError, but no exception was raised")
def test_body_exception_suppress(self):
def suppress_exc(*exc_details):
return True
try:
with ExitStack() as stack:
stack.push(suppress_exc)
1/0
except IndexError as exc:
self.fail("Expected no exception, got IndexError")
def test_exit_exception_chaining_suppress(self):
with ExitStack() as stack:
stack.push(lambda *exc: True)
stack.push(lambda *exc: 1/0)
stack.push(lambda *exc: {}[1])
def test_excessive_nesting(self):
# The original implementation would die with RecursionError here
with ExitStack() as stack:
for i in range(10000):
stack.callback(int)
def test_instance_bypass(self):
class Example(object): pass
cm = Example()
cm.__exit__ = object()
stack = ExitStack()
self.assertRaises(AttributeError, stack.enter_context, cm)
stack.push(cm)
self.assertIs(stack._exit_callbacks[-1], cm)
# This is needed to make the test actually run under regrtest.py!
def test_main():
support.run_unittest(__name__)
if __name__ == "__main__":
test_main()
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<th>Function </th><th>Purpose </th></tr>
<tr>
<td><a class="el" href="group___l_a_p_l.html#ga8850042eed51777866d7bd0d050cfdc2" title="Sets the external link traversal callback function in a link access property list.">H5Pset_elink_cb</a>/<a class="el" href="group___l_a_p_l.html#gacbf576bd8f7e63f3a91134b12d6b2d12" title="Retrieves the external link traversal callback function from the specified link access property list.">H5Pget_elink_cb</a> </td><td>Sets/gets the external link traversal callback function. </td></tr>
<tr>
<td><a class="el" href="group___l_a_p_l.html#ga020f7eb2eae01043286af50db0a76d82" title="Sets the external link traversal file access flag in a link access property list.">H5Pset_elink_acc_flags</a>/<a class="el" href="group___l_a_p_l.html#gaf1357eb0940f171efecae06a9ed6155b" title="Retrieves the external link traversal file access flag from the specified link access property list.">H5Pget_elink_acc_flags</a> </td><td>Sets/gets the external link traversal file access flag. </td></tr>
<tr>
<td><a class="el" href="group___l_a_p_l.html#ga3895e8e60ce8f0b6f32ab7a22c715d1a" title="Sets a file access property list for use in accessing a file pointed to by an external link.">H5Pset_elink_fapl</a>/<a class="el" href="group___l_a_p_l.html#ga2c2fe0a0396b9a0a02b28402e4ee108a" title="Retrieves the file access property list identifier associated with the link access property list.">H5Pget_elink_fapl</a> </td><td>Sets/gets a file access property list for use in accessing a file pointed to by an external link </td></tr>
<tr>
<td><a class="el" href="group___l_a_p_l.html#gafa5eced13ba3a00cdd65669626dc7294" title="Sets prefix to be applied to external link paths.">H5Pset_elink_prefix</a>/<a class="el" href="group___l_a_p_l.html#ga7960f746797bcf35f70746cd644f8b5a" title="Retrieves prefix applied to external link paths.">H5Pget_elink_prefix</a> </td><td>Sets/gets prefix to be applied to external link paths. </td></tr>
<tr>
<td><a class="el" href="group___l_a_p_l.html#gaa46c63c196a0cf5cd94dede039c030f4" title="Sets maximum number of soft or user-defined link traversals.">H5Pset_nlinks</a>/<a class="el" href="group___l_a_p_l.html#ga6bfa33fa9a77011cbdc06d0fbc907177" title="Retrieves the maximum number of link traversals.">H5Pget_nlinks</a> </td><td>Sets/gets maximum number of soft or user-defined link traversals. </td></tr>
</table>
</p>
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Modules</h2></td></tr>
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Functions</h2></td></tr>
<tr class="memitem:gaf1357eb0940f171efecae06a9ed6155b"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___l_a_p_l.html#gaf1357eb0940f171efecae06a9ed6155b">H5Pget_elink_acc_flags</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> lapl_id, unsigned *flags)</td></tr>
<tr class="memdesc:gaf1357eb0940f171efecae06a9ed6155b"><td class="mdescLeft"> </td><td class="mdescRight">Retrieves the external link traversal file access flag from the specified link access property list. <a href="group___l_a_p_l.html#gaf1357eb0940f171efecae06a9ed6155b">More...</a><br /></td></tr>
<tr class="separator:gaf1357eb0940f171efecae06a9ed6155b"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:gacbf576bd8f7e63f3a91134b12d6b2d12"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___l_a_p_l.html#gacbf576bd8f7e63f3a91134b12d6b2d12">H5Pget_elink_cb</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> lapl_id, <a class="el" href="_h5_lpublic_8h.html#a96345937d04b66a13baec1ef1a6cff76">H5L_elink_traverse_t</a> *func, void **op_data)</td></tr>
<tr class="memdesc:gacbf576bd8f7e63f3a91134b12d6b2d12"><td class="mdescLeft"> </td><td class="mdescRight">Retrieves the external link traversal callback function from the specified link access property list. <a href="group___l_a_p_l.html#gacbf576bd8f7e63f3a91134b12d6b2d12">More...</a><br /></td></tr>
<tr class="separator:gacbf576bd8f7e63f3a91134b12d6b2d12"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga2c2fe0a0396b9a0a02b28402e4ee108a"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___l_a_p_l.html#ga2c2fe0a0396b9a0a02b28402e4ee108a">H5Pget_elink_fapl</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> lapl_id)</td></tr>
<tr class="memdesc:ga2c2fe0a0396b9a0a02b28402e4ee108a"><td class="mdescLeft"> </td><td class="mdescRight">Retrieves the file access property list identifier associated with the link access property list. <a href="group___l_a_p_l.html#ga2c2fe0a0396b9a0a02b28402e4ee108a">More...</a><br /></td></tr>
<tr class="separator:ga2c2fe0a0396b9a0a02b28402e4ee108a"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga7960f746797bcf35f70746cd644f8b5a"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#af629ed855824cf5955b54529adf78ad6">ssize_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___l_a_p_l.html#ga7960f746797bcf35f70746cd644f8b5a">H5Pget_elink_prefix</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> plist_id, char *prefix, size_t size)</td></tr>
<tr class="memdesc:ga7960f746797bcf35f70746cd644f8b5a"><td class="mdescLeft"> </td><td class="mdescRight">Retrieves prefix applied to external link paths. <a href="group___l_a_p_l.html#ga7960f746797bcf35f70746cd644f8b5a">More...</a><br /></td></tr>
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<tr class="memitem:ga6bfa33fa9a77011cbdc06d0fbc907177"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___l_a_p_l.html#ga6bfa33fa9a77011cbdc06d0fbc907177">H5Pget_nlinks</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> plist_id, size_t *nlinks)</td></tr>
<tr class="memdesc:ga6bfa33fa9a77011cbdc06d0fbc907177"><td class="mdescLeft"> </td><td class="mdescRight">Retrieves the maximum number of link traversals. <a href="group___l_a_p_l.html#ga6bfa33fa9a77011cbdc06d0fbc907177">More...</a><br /></td></tr>
<tr class="separator:ga6bfa33fa9a77011cbdc06d0fbc907177"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga020f7eb2eae01043286af50db0a76d82"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___l_a_p_l.html#ga020f7eb2eae01043286af50db0a76d82">H5Pset_elink_acc_flags</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> lapl_id, unsigned flags)</td></tr>
<tr class="memdesc:ga020f7eb2eae01043286af50db0a76d82"><td class="mdescLeft"> </td><td class="mdescRight">Sets the external link traversal file access flag in a link access property list. <a href="group___l_a_p_l.html#ga020f7eb2eae01043286af50db0a76d82">More...</a><br /></td></tr>
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<tr class="memitem:ga8850042eed51777866d7bd0d050cfdc2"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___l_a_p_l.html#ga8850042eed51777866d7bd0d050cfdc2">H5Pset_elink_cb</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> lapl_id, <a class="el" href="_h5_lpublic_8h.html#a96345937d04b66a13baec1ef1a6cff76">H5L_elink_traverse_t</a> func, void *op_data)</td></tr>
<tr class="memdesc:ga8850042eed51777866d7bd0d050cfdc2"><td class="mdescLeft"> </td><td class="mdescRight">Sets the external link traversal callback function in a link access property list. <a href="group___l_a_p_l.html#ga8850042eed51777866d7bd0d050cfdc2">More...</a><br /></td></tr>
<tr class="separator:ga8850042eed51777866d7bd0d050cfdc2"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga3895e8e60ce8f0b6f32ab7a22c715d1a"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___l_a_p_l.html#ga3895e8e60ce8f0b6f32ab7a22c715d1a">H5Pset_elink_fapl</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> lapl_id, <a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> fapl_id)</td></tr>
<tr class="memdesc:ga3895e8e60ce8f0b6f32ab7a22c715d1a"><td class="mdescLeft"> </td><td class="mdescRight">Sets a file access property list for use in accessing a file pointed to by an external link. <a href="group___l_a_p_l.html#ga3895e8e60ce8f0b6f32ab7a22c715d1a">More...</a><br /></td></tr>
<tr class="separator:ga3895e8e60ce8f0b6f32ab7a22c715d1a"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:gafa5eced13ba3a00cdd65669626dc7294"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___l_a_p_l.html#gafa5eced13ba3a00cdd65669626dc7294">H5Pset_elink_prefix</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> plist_id, const char *prefix)</td></tr>
<tr class="memdesc:gafa5eced13ba3a00cdd65669626dc7294"><td class="mdescLeft"> </td><td class="mdescRight">Sets prefix to be applied to external link paths. <a href="group___l_a_p_l.html#gafa5eced13ba3a00cdd65669626dc7294">More...</a><br /></td></tr>
<tr class="separator:gafa5eced13ba3a00cdd65669626dc7294"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:gaa46c63c196a0cf5cd94dede039c030f4"><td class="memItemLeft" align="right" valign="top"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group___l_a_p_l.html#gaa46c63c196a0cf5cd94dede039c030f4">H5Pset_nlinks</a> (<a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> plist_id, size_t nlinks)</td></tr>
<tr class="memdesc:gaa46c63c196a0cf5cd94dede039c030f4"><td class="mdescLeft"> </td><td class="mdescRight">Sets maximum number of soft or user-defined link traversals. <a href="group___l_a_p_l.html#gaa46c63c196a0cf5cd94dede039c030f4">More...</a><br /></td></tr>
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<h2 class="groupheader">Function Documentation</h2>
<a id="gaf1357eb0940f171efecae06a9ed6155b"></a>
<h2 class="memtitle"><span class="permalink"><a href="#gaf1357eb0940f171efecae06a9ed6155b">◆ </a></span>H5Pget_elink_acc_flags()</h2>
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<td class="memname"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> H5Pget_elink_acc_flags </td>
<td>(</td>
<td class="paramtype"><a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> </td>
<td class="paramname"><em>lapl_id</em>, </td>
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<td class="paramkey"></td>
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<td class="paramtype">unsigned * </td>
<td class="paramname"><em>flags</em> </td>
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<p>Retrieves the external link traversal file access flag from the specified link access property list. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">lapl_id</td><td>Link access property list identifier </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">flags</td><td>File access flag for link traversal</td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>Returns a non-negative value if successful; otherwise, returns a negative value.</dd></dl>
<p><a class="el" href="group___l_a_p_l.html#gaf1357eb0940f171efecae06a9ed6155b" title="Retrieves the external link traversal file access flag from the specified link access property list.">H5Pget_elink_acc_flags()</a> retrieves the file access flag used to open an external link target file from the specified link access property list.</p>
<p>Valid values for <code>flags</code> include: </p><ul>
<li><a class="el" href="_h5_fpublic_8h.html#a402673dec5c537b27a49a9a8bd6140b4">H5F_ACC_RDWR</a> - Files opened through external links will be opened with write access </li>
<li><a class="el" href="_h5_fpublic_8h.html#a1c406ffa89f4acf5a332144a2683d394">H5F_ACC_RDONLY</a> - Files opened through external links will be opened with read-only access </li>
<li><a class="el" href="_h5_fpublic_8h.html#ab0ce75eb6c23c77bf2736d53e2ea5dce">H5F_ACC_DEFAULT</a> - Files opened through external links will be opened with the same access flag as the parent file</li>
</ul>
<p>The value returned, if it is not <a class="el" href="_h5_fpublic_8h.html#ab0ce75eb6c23c77bf2736d53e2ea5dce">H5F_ACC_DEFAULT</a>, will override the default access flag, which is the access flag used to open the parent file.</p>
<p><b>Example Usage:</b> The following code retrieves the external link access flag settings on the link access property list <code>lapl_id</code> into a local variable: </p><pre>
unsigned acc_flags;
status = H5Pget_elink_acc_flags(lapl_id, &acc_flags);
</pre><dl class="section since"><dt>Since</dt><dd>1.8.3 </dd></dl>
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<a id="gacbf576bd8f7e63f3a91134b12d6b2d12"></a>
<h2 class="memtitle"><span class="permalink"><a href="#gacbf576bd8f7e63f3a91134b12d6b2d12">◆ </a></span>H5Pget_elink_cb()</h2>
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<td class="memname"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> H5Pget_elink_cb </td>
<td>(</td>
<td class="paramtype"><a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> </td>
<td class="paramname"><em>lapl_id</em>, </td>
</tr>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="_h5_lpublic_8h.html#a96345937d04b66a13baec1ef1a6cff76">H5L_elink_traverse_t</a> * </td>
<td class="paramname"><em>func</em>, </td>
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<td class="paramtype">void ** </td>
<td class="paramname"><em>op_data</em> </td>
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<p>Retrieves the external link traversal callback function from the specified link access property list. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">lapl_id</td><td>Link access property list identifier </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">func</td><td>User-defined external link traversal callback function </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">op_data</td><td>User-defined input data for the callback function</td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>Returns a non-negative value if successful; otherwise, returns a negative value.</dd></dl>
<p><a class="el" href="group___l_a_p_l.html#gacbf576bd8f7e63f3a91134b12d6b2d12" title="Retrieves the external link traversal callback function from the specified link access property list.">H5Pget_elink_cb()</a> retrieves the user-defined external link traversal callback function defined in the specified link access property list.</p>
<p>The callback function may adjust the file access property list and file access flag to use when opening a file through an external link. The callback will be executed by the HDF5 library immediately before opening the target file.</p>
<p><b>Failure Modes:</b> <a class="el" href="group___l_a_p_l.html#gacbf576bd8f7e63f3a91134b12d6b2d12" title="Retrieves the external link traversal callback function from the specified link access property list.">H5Pget_elink_cb()</a> will fail if the link access property list identifier, <code>lapl_id</code>, is invalid.</p>
<p>An invalid function pointer or data pointer, <code>func</code> or <code>op_data</code> respectively, may cause a segmentation fault or an invalid memory access.</p>
<p><b>Example Usage:</b> The following code retrieves the external link callback settings on the link access property list <code>lapl_id</code> into local variables: </p><pre>
H5L_elink_traverse_t elink_callback_func;
void *elink_callback_udata;
status = H5Pget_elink_cb (lapl_id, &elink_callback_func,
&elink_callback_udata);
</pre><dl class="section since"><dt>Since</dt><dd>1.8.3 </dd></dl>
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<h2 class="memtitle"><span class="permalink"><a href="#ga2c2fe0a0396b9a0a02b28402e4ee108a">◆ </a></span>H5Pget_elink_fapl()</h2>
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<td class="memname"><a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> H5Pget_elink_fapl </td>
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<p>Retrieves the file access property list identifier associated with the link access property list. </p>
<dl class="params"><dt>Parameters</dt><dd>
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<tr><td class="paramdir">[in]</td><td class="paramname">lapl_id</td><td>Link access property list identifier</td></tr>
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<dl class="section return"><dt>Returns</dt><dd>Returns a file access property list identifier if successful; otherwise returns <a class="el" href="_h5_ipublic_8h.html#a01eab13dccc91afd6909d74dccb780ba">H5I_INVALID_HID</a>.</dd></dl>
<p><a class="el" href="group___l_a_p_l.html#ga2c2fe0a0396b9a0a02b28402e4ee108a" title="Retrieves the file access property list identifier associated with the link access property list.">H5Pget_elink_fapl()</a> retrieves the file access property list identifier that is set for the link access property list identifier, <code>lapl_id</code>. The library uses this file access property list identifier to open the target file for the external link access. When no such identifier is set, this routine returns <a class="el" href="_h5_ppublic_8h.html#afa85e97bfbf9bf1c58e39263846c568f">H5P_DEFAULT</a>.</p>
<dl class="section see"><dt>See also</dt><dd><a class="el" href="group___l_a_p_l.html#ga3895e8e60ce8f0b6f32ab7a22c715d1a" title="Sets a file access property list for use in accessing a file pointed to by an external link.">H5Pset_elink_fapl()</a> and <a class="el" href="group___h5_l.html#ga15dfaeb9b1c0b3136533cb97ee45e683" title="Creates an external link, a soft link to an object in a different file.">H5Lcreate_external()</a>.</dd></dl>
<dl class="section since"><dt>Since</dt><dd>1.8.0 </dd></dl>
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<h2 class="memtitle"><span class="permalink"><a href="#ga7960f746797bcf35f70746cd644f8b5a">◆ </a></span>H5Pget_elink_prefix()</h2>
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<td class="memname"><a class="el" href="_h5public_8h.html#af629ed855824cf5955b54529adf78ad6">ssize_t</a> H5Pget_elink_prefix </td>
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<td class="paramtype"><a class="el" href="_h5_ipublic_8h.html#a0045db7ff9c22ad35db6ae91662e1943">hid_t</a> </td>
<td class="paramname"><em>plist_id</em>, </td>
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<td class="paramtype">char * </td>
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<p>Retrieves prefix applied to external link paths. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">plist_id</td><td>Link access property list identifier </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">prefix</td><td>Prefix applied to external link paths </td></tr>
<tr><td class="paramdir">[in]</td><td class="paramname">size</td><td>Size of prefix, including null terminator</td></tr>
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<dl class="section return"><dt>Returns</dt><dd>If successful, returns a non-negative value specifying the size in bytes of the prefix without the NULL terminator; otherwise returns a negative value.</dd></dl>
<p><a class="el" href="group___l_a_p_l.html#ga7960f746797bcf35f70746cd644f8b5a" title="Retrieves prefix applied to external link paths.">H5Pget_elink_prefix()</a> retrieves the prefix applied to the path of any external links traversed.</p>
<p>When an external link is traversed, the prefix is retrieved from the link access property list <code>plist_id</code>, returned in the user-allocated buffer pointed to by <code>prefix</code>, and prepended to the filename stored in the external link.</p>
<p>The size in bytes of the prefix, including the NULL terminator, is specified in <code>size</code>. If size is unknown, a preliminary <a class="el" href="group___l_a_p_l.html#ga7960f746797bcf35f70746cd644f8b5a" title="Retrieves prefix applied to external link paths.">H5Pget_elink_prefix()</a> call with the pointer <code>prefix</code> set to NULL will return the size of the prefix without the NULL terminator.</p>
<dl class="section since"><dt>Since</dt><dd>1.8.0 </dd></dl>
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<h2 class="memtitle"><span class="permalink"><a href="#ga6bfa33fa9a77011cbdc06d0fbc907177">◆ </a></span>H5Pget_nlinks()</h2>
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<td class="memname"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> H5Pget_nlinks </td>
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<p>Retrieves the maximum number of link traversals. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">plist_id</td><td>Link access property list identifier </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">nlinks</td><td>Maximum number of links to traverse</td></tr>
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<dl class="section return"><dt>Returns</dt><dd>Returns a non-negative value if successful; otherwise, returns a negative value.</dd></dl>
<p><a class="el" href="group___l_a_p_l.html#ga6bfa33fa9a77011cbdc06d0fbc907177" title="Retrieves the maximum number of link traversals.">H5Pget_nlinks()</a> retrieves the maximum number of soft or user-defined link traversals allowed, <code>nlinks</code>, before the library assumes it has found a cycle and aborts the traversal. This value is retrieved from the link access property list <code>plist_id</code>.</p>
<p>The limit on the number of soft or user-defined link traversals is designed to terminate link traversal if one or more links form a cycle. User control is provided because some files may have legitimate paths formed of large numbers of soft or user-defined links. This property can be used to allow traversal of as many links as desired.</p>
<dl class="section since"><dt>Since</dt><dd>1.8.0 </dd></dl>
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<h2 class="memtitle"><span class="permalink"><a href="#ga020f7eb2eae01043286af50db0a76d82">◆ </a></span>H5Pset_elink_acc_flags()</h2>
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<td class="memname"><a class="el" href="_h5public_8h.html#a3b079ecf932a5c599499cf7e298af160">herr_t</a> H5Pset_elink_acc_flags </td>
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<p>Sets the external link traversal file access flag in a link access property list. </p>
<dl class="params"><dt>Parameters</dt><dd>
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