RWThreadAttributeRWHandleBase
#include <rw/thread/RWThreadAttribute.h>
Class RWThreadAttribute encapsulates a set of attributes that define or control thread scheduling and stack allocation. By supplying an instance of this class to a thread object such as an RWThread you can configure the behavior of each new thread that you create. You can also use an RWThreadAttribute to retrieve the default values for the current environment and query the current environment as to which attributes may be legally retrieved and set under the current circumstances. This class also provides functions for querying the minimum and maximum allowable values for the various attributes. Please see the Threads.h++ User's Guide and the Threads.h++ Platform User's Guide for a complete discussion of thread attributes.
#include <rw/thread/RWThreadAttribute.h> // for RWThreadAttribute
#include <rw/thread/RWRunnableSelf.h> // for rwThread()
#include <rw/thread/rwtMakeThreadFunction.h> // for rwtMakeThreadFunction()
void checkContentionScope(void)
{
RWThreadSelf me = rwThread();
// Was this thread created by a Threading package class?
if (me.isValid()) {
// Get the attribute instance used to create the thread
RWThreadAttribute attr = me.getActiveAttribute();
// Is the contention scope attribute available?
if (attr.canGetContentionScope()) {
// Yes, then get the scope used to create the thread
RWContentionScope cscope = attr.getContentionScope();
switch (cscope) {
case RW_THR_PROCESS_SCOPE:
cout << "Process Scope" << endl;
break;
case RW_THR_SYSTEM_SCOPE:
cout << "System Scope" << endl;
break;
default:
cout << "Unexpected value for contention scope"
<< endl;
}
}
else
cout << "Contention scope is not supported" << endl;
}
}
int main()
{
RWThread t1 = rwtMakeThreadFunction(checkContentionScope);
cout << "Default: " << flush;
t1.start();
t1.join();
RWThreadAttribute attr;
// Is the desired contention scope policy supported?
if (attr.canSetContentionScope(RW_THR_SYSTEM_SCOPE))
attr.setContentionScope(RW_THR_SYSTEM_SCOPE);
else
cout << "Unable to set contention scope to \"System\""
<< endl;
t1.setAttribute(attr);
cout << "Set: " << flush;
t1.start();
t1.join();
attr.resetContentionScope();
t1.setAttribute(attr);
cout << "Reset: " << flush;
t1.start();
t1.join();
}
/*
* OUTPUT (Solaris):
*
Default: Process Scope
Set: System Scope
Reset: Process Scope
*
*/
enum RWConcurrencyPolicy
For a description of this global enumerator, which is defined in RWThreadAttribute.h, see the reference entry for RWConcurrencyPolicy.
enum RWContentionScope
For a description of this global enumerator, which is defined in RWThreadAttribute.h, see the reference entry for RWContentionScope.
enum RWInheritancePolicy
For a description of this global enumerator, which is defined in RWThreadAttribute.h, see the reference entry for RWInheritancePolicy.
enum RWSchedulingPolicy {
For a description of this global enumerator, which is defined in RWThreadAttribute.h, see the reference entry for RWSchedulingPolicy.
enum RWStartPolicy {
For a description of this global enumerator, which is defined in RWThreadAttribute.h, see the reference entry for RWStartPolicy.
typedef int RWPriority; // OS/2, POSIX, Win32 typedef pri_t RWPriority; // SOLARIS
RW_THR_HAS_CONCURRENCY_SCOPE RW_THR_HAS_CONTENTION_SCOPE RW_THR_HAS_INHERITANCE_POLICY RW_THR_HAS_PRIORITY RW_THR_HAS_PROCESS_SCOPE_PRIORITY RW_THR_HAS_SCHEDULING_POLICY RW_THR_HAS_STACK_COMMIT_SIZE RW_THR_HAS_STACK_RESERVE_SIZE RW_THR_HAS_START_POLICY RW_THR_HAS_SYSTEM_SCOPE_PRIORITY RW_THR_HAS_TIME_SLICE_QUANTUM RW_THR_HAS_USER_STACK
These macros, defined in rw/thr/defs.h, are used to indicate whether the corresponding attribute is supported in the current environment. If the macro is not defined, attempts to get or set the corresponding attribute will produce exceptions. If the macro is defined, the current environment has some level of support for the attribute, and may allow you to get or set the attribute value.
RW_THR_HAS_DUAL_PRIORITY
This macro indicates that the underlying system requires two priorities for threads with system contention scope-one priority value for use in resolving system-level scheduling conflicts, and a second priority value for use in resolving contention for synchronization resources that are shared between threads within a process.
RW_THR_HAS_PARTIAL_STACK_COMMITMENT
This macro indicates that the underlying system allows partial stack commitment, meaning the stack commit size may be set to a value less that the stack reserve size. If this macro is not defined, then the stack reserve size and stack commit size attributes are mutually exclusive and only one or the other may be set.
RWThreadAttribute(void);
Default constructor.
RWThreadAttribute(RWStaticCtor);
Constructs a global static instance. The object will be initialized upon first use, and if the object is used before this constructor is called, any set values will not be overridden.
RWThreadAttribute(const RWThreadAttribute& second)
Copy constructor.
void copy(const RWThreadAttribute& second);
Copies the thread attribute values from second.
RWBoolean isEqual(const RWThreadAttribute& second) const;
Tests the equality of self against second on a value by value basis. Possible exceptions include RWTHRInternalError.
The bulk of the public member functions for this class are divided into 6 groups:
The "canGet" functions determine whether an attribute value can be read.
The "canSet" functions determine whether an attribute value can be set.
The "get" functions return an attribute value.
The "isXxxSet" functions determine whether an attribute has maintained its previously set value.
The "reset" functions restore an attribute to its default setting.
The "set" functions set an attribute value.
RWBoolean canGetConcurrencyPolicy(void) const; RWBoolean canGetContentionScope(void) const; RWBoolean canGetInheritancePolicy(void) const; RWBoolean canGetPriority(void) const; RWBoolean canGetProcessScopePriority(void) const; RWBoolean canGetSchedulingPolicy(void) const; RWBoolean canGetStackCommitSize(void) const; RWBoolean canGetStackReserveSize(void) const; RWBoolean canGetStartPolicy(void) const; RWBoolean canGetSystemScopePriority(void) const; RWBoolean canGetTimeSliceQuantum(void) const; RWBoolean canGetUserStack(void) const;
These "canGet" test functions determine at runtime whether the corresponding attribute value may be read. Each of these functions returns FALSE if the corresponding attribute is not supported in the current environment, or if the corresponding "get" function cannot return a legal value under current circumstances.
If the corresponding attribute value has not yet been "set", then a return value of TRUE indicates that a default value is available and may be read.
These functions always return TRUE if the corresponding attribute still has the value previously defined by a call to the matching "set" function. In this case the behavior is similar to that provided by the "isSet" functions, below. Possible exceptions include RWTHRInternalError.
RWBoolean canSetConcurrencyPolicy(RWConcurrencyPolicy policy) const; RWBoolean canSetContentionScope(RWContentionScope scope) const; RWBoolean canSetInheritancePolicy(RWInheritancePolicy policy) const; RWBoolean canSetPriority(void) const; RWBoolean canSetProcessScopePriority(void) const; RWBoolean canSetSchedulingPolicy(RWSchedulingPolicy policy) const; RWBoolean canSetStackCommitSize(void) const; RWBoolean canSetStackReserveSize(void) const; RWBoolean canSetStartPolicy(RWStartPolicy policy) const; RWBoolean canSetSystemScopePriority(void) const; RWBoolean canSetTimeSliceQuantum(void) const; RWBoolean canSetUserStack(void) const;
The "canSet" test functions determine, at runtime, whether the corresponding attribute value may be set. Each of these functions returns FALSE if the corresponding attribute is not supported in the current environment or if the specified policy, if any, is not supported under the current circumstances. Otherwise, the function returns TRUE. All of these functions can throw an RWTHRInternalError exception. In addition, those that take an argument can throw RWTHRBoundsError.
RWConcurrencyPolicy getConcurrencyPolicy(void) const; RWContentionScope getContentionScope(void) const; RWInheritancePolicy getInheritancePolicy(void) const; RWPriority getPriority(void) const; RWPriority getProcessScopePriority(void) const; RWSchedulingPolicy getSchedulingPolicy(void) const; size_t getStackCommitSize(void) const; size_t getStackReserveSize(void) const; RWStartPolicy getStartPolicy(void) const; RWPriority getSystemScopePriority(void) const; unsigned long getTimeSliceQuantum(void) const; void* getUserStackAddress(void) const; size_t getUserStackSize(void) const;
Use these functions to query the default value of an attribute, if available, or the last value defined in a call to the matching "set" function.
These functions will throw an RWTHROperationNotSupported exception if the attribute is not supported in the current environment. They will throw the RWTHROperationNotAvailable exception if the corresponding attribute is supported but has not yet been defined by a call to the matching "set" function, and no default value is available under the current circumstances. Other possible exceptions include RWTHRInternalError.
RWPriority getMaxPriority(void) const; RWPriority getMaxProcessScopePriority(void) const; RWPriority getMaxSystemScopePriority(void) const; unsigned long getMaxTimeSliceQuantum(void) const; RWPriority getMinPriority(void) const; RWPriority getMinProcessScopePriority(void) const; static size_t getMinStackSize(void); RWPriority getMinSystemScopePriority(void) const; unsigned long getMinTimeSliceQuantum(void) const;
Use these functions to determine the legal range of values for the various attributes. All of these functions can throw exceptions RWTHROperationNotSupported and RWTHRInternalError. In addition, all of these functions except getMinStackSize() can throw an RWTHROperationNotAvailable exception.
RWBoolean isConcurrencyPolicySet(void) const; RWBoolean isContentionScopeSet(void) const; RWBoolean isInheritancePolicySet(void) const; RWBoolean isPrioritySet(void) const; RWBoolean isProcessScopePrioritySet(void) const; RWBoolean isSchedulingPolicySet(void) const; RWBoolean isStackCommitSizeSet(void) const; RWBoolean isStackReserveSizeSet(void) const; RWBoolean isStartPolicySet(void) const; RWBoolean isSystemScopePrioritySet(void) const; RWBoolean isTimeSliceQuantumSet(void) const; RWBoolean isUserStackSet(void) const;
The "isXxxSet" test functions determine whether the corresponding attribute still has the value specified in an earlier call to the matching "set" function.
Each of these functions returns FALSE if the corresponding attribute is not supported in the current environment, has not yet been set, or has been forced to some other default value in response to a change in another related attribute. Otherwise TRUE is returned. Possible exceptions include RWTHRInternalError.
void resetConcurrencyPolicy(void);
void resetContentionScope(void);
void resetInheritancePolicy(void);
void resetPriority(void);
void resetProcessScopePriority(void);
void resetSchedulingPolicy(void);
void resetStackCommitSize(void);
void resetStackReserveSize(void);
void resetStartPolicy(void);
void resetSystemScopePriority(void);
void resetTimeSliceQuantum(void);
void resetUserStack(void);
These functions will restore an attribute value to its default setting, if any. These functions will always succeed, even if the target attribute is not supported in the current environment. There are several combinations of attributes and environments where it is not possible to query for a default value of an attribute. In those cases, the functions will simply clear any previous setting so that Threads.h++ will know to rely on the underlying API to determine the appropriate default value. Possible exceptions include RWTHRInternalError and RWTHROperationNotSupported.
void setConcurrencyPolicy(RWConcurrencyPolicy policy);
void setContentionScope(RWContentionScope scope);
void setInheritancePolicy(RWInheritancePolicy policy); void setPriority(RWPriority priority); void setProcessScopePriority(RWPriority priority);
void setSchedulingPolicy(RWSchedulingPolicy policy); void setStackCommitSize(size_t size);
void setStackReserveSize(size_t size);
void setStartPolicy(RWStartPolicy policy);
void setSystemScopePriority(RWPriority priority);
void setTimeSliceQuantum(unsigned long milliseconds);
void setUserStack(void* address, size_t size);
Use these functions to set the corresponding attribute. The functions will throw the RWTHROperationNotSupported exception if the attribute is not supported in the current environment. They will throw the RWTHROperationNotAvaiable exception if the corresponding attribute is supported but the specified value is not supported under the current circumstances. Possible exceptions include RWTHRBoundsError, RWTHROperationNotAvailable, RWTHROperationNotSupported, and RWTHRInternalError.
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