hwlocality_setsource(3) Library Functions Manual hwlocality_setsource(3)
NAME
hwlocality_setsource - Changing the Source of Topology Discovery
SYNOPSIS
Enumerations
enum hwloc_topology_components_flag_e {
HWLOC_TOPOLOGY_COMPONENTS_FLAG_BLACKLIST }
Functions
int hwloc_topology_set_pid (hwloc_topology_t restrict topology,
hwloc_pid_t pid)
int hwloc_topology_set_synthetic (hwloc_topology_t restrict topology,
const char *restrict description)
int hwloc_topology_set_xml (hwloc_topology_t restrict topology, const
char *restrict xmlpath)
int hwloc_topology_set_xmlbuffer (hwloc_topology_t restrict topology,
const char *restrict buffer, int size)
int hwloc_topology_set_components (hwloc_topology_t restrict topology,
unsigned long flags, const char *restrict name)
Detailed Description
These functions must be called between hwloc_topology_init() and
hwloc_topology_load(). Otherwise, they will return -1 with errno set to
EBUSY.
If none of the functions below is called, the default is to detect all
the objects of the machine that the caller is allowed to access.
This default behavior may also be modified through environment variables
if the application did not modify it already. Setting HWLOC_XMLFILE in
the environment enforces the discovery from a XML file as if
hwloc_topology_set_xml() had been called. Setting HWLOC_SYNTHETIC
enforces a synthetic topology as if hwloc_topology_set_synthetic() had
been called.
Finally, HWLOC_THISSYSTEM enforces the return value of
hwloc_topology_is_thissystem().
Enumeration Type Documentation
enum hwloc_topology_components_flag_e
Flags to be passed to hwloc_topology_set_components()
Enumerator
HWLOC_TOPOLOGY_COMPONENTS_FLAG_BLACKLIST
Blacklist the target component from being used.
Function Documentation
int hwloc_topology_set_components (hwloc_topology_t restrict topology,
unsigned long flags, const char *restrict name)
Prevent a discovery component from being used for a topology. name is
the name of the discovery component that should not be used when loading
topology topology. The name is a string such as 'cuda'.
For components with multiple phases, it may also be suffixed with the
name of a phase, for instance 'linux:io'.
flags should be HWLOC_TOPOLOGY_COMPONENTS_FLAG_BLACKLIST.
This may be used to avoid expensive parts of the discovery process. For
instance, CUDA-specific discovery may be expensive and unneeded while
generic I/O discovery could still be useful.
Returns
0 on success.
-1 on error, for instance if flags are invalid.
int hwloc_topology_set_pid (hwloc_topology_t restrict topology, hwloc_pid_t
pid)
Change which process the topology is viewed from. On some systems,
processes may have different views of the machine, for instance the set
of allowed CPUs. By default, hwloc exposes the view from the current
process. Calling hwloc_topology_set_pid() permits to make it expose the
topology of the machine from the point of view of another process.
Note
hwloc_pid_t is pid_t on Unix platforms, and HANDLE on native Windows
platforms.
-1 is returned and errno is set to ENOSYS on platforms that do not
support this feature.
The PID will not actually be used until hwloc_topology_load(). If
the corresponding process exits in the meantime, hwloc will ignore
the PID. If another process reuses the PID, the view of that process
will be used.
Returns
0 on success, -1 on error.
int hwloc_topology_set_synthetic (hwloc_topology_t restrict topology, const
char *restrict description)
Enable synthetic topology. Gather topology information from the given
description, a space-separated string of <type:number> describing the
object type and arity at each level. All types may be omitted (space-
separated string of numbers) so that hwloc chooses all types according
to usual topologies. See also the Synthetic topologies.
Setting the environment variable HWLOC_SYNTHETIC may also result in this
behavior.
If description was properly parsed and describes a valid topology
configuration, this function returns 0. Otherwise -1 is returned and
errno is set to EINVAL.
Note that this function does not actually load topology information; it
just tells hwloc where to load it from. You'll still need to invoke
hwloc_topology_load() to actually load the topology information.
Returns
0 on success.
-1 with errno set to EINVAL if the description was invalid.
Note
For convenience, this backend provides empty binding hooks which
just return success.
On success, the synthetic component replaces the previously enabled
component (if any), but the topology is not actually modified until
hwloc_topology_load().
int hwloc_topology_set_xml (hwloc_topology_t restrict topology, const char
*restrict xmlpath)
Enable XML-file based topology. Gather topology information from the XML
file given at xmlpath. Setting the environment variable HWLOC_XMLFILE
may also result in this behavior. This file may have been generated
earlier with hwloc_topology_export_xml() in hwloc/export.h, or lstopo
file.xml.
Note that this function does not actually load topology information; it
just tells hwloc where to load it from. You'll still need to invoke
hwloc_topology_load() to actually load the topology information.
Returns
0 on success.
-1 with errno set to EINVAL on failure to read the XML file.
Note
See also hwloc_topology_set_userdata_import_callback() for importing
application-specific object userdata.
For convenience, this backend provides empty binding hooks which
just return success. To have hwloc still actually call OS-specific
hooks, the HWLOC_TOPOLOGY_FLAG_IS_THISSYSTEM has to be set to assert
that the loaded file is really the underlying system.
On success, the XML component replaces the previously enabled
component (if any), but the topology is not actually modified until
hwloc_topology_load().
If an invalid XML input file is given, the error may be reported
either here or later by hwloc_topology_load() depending on the XML
library used by hwloc.
int hwloc_topology_set_xmlbuffer (hwloc_topology_t restrict topology, const
char *restrict buffer, int size)
Enable XML based topology using a memory buffer (instead of a file, as
with hwloc_topology_set_xml()). Gather topology information from the XML
memory buffer given at buffer and of length size (including an ending
\0). This buffer may have been filled earlier with
hwloc_topology_export_xmlbuffer() in hwloc/export.h.
Note that this function does not actually load topology information; it
just tells hwloc where to load it from. You'll still need to invoke
hwloc_topology_load() to actually load the topology information.
Returns
0 on success.
-1 with errno set to EINVAL on failure to read the XML buffer.
Note
See also hwloc_topology_set_userdata_import_callback() for importing
application-specific object userdata.
For convenience, this backend provides empty binding hooks which
just return success. To have hwloc still actually call OS-specific
hooks, the HWLOC_TOPOLOGY_FLAG_IS_THISSYSTEM has to be set to assert
that the loaded file is really the underlying system.
On success, the XML component replaces the previously enabled
component (if any), but the topology is not actually modified until
hwloc_topology_load().
If an invalid XML input file is given, the error may be reported
either here or later by hwloc_topology_load() depending on the XML
library used by hwloc.
Author
Generated automatically by Doxygen for Hardware Locality (hwloc) from
the source code.
Hardware Locality (hwloc) Version 2.12.0 hwlocality_setsource(3)
Generated by dwww version 1.16 on Sat Oct 3 06:01:03 CEST 2026.