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libc/semaphore:  Add nxsem_getvalue() which is identical to sem_getvalue() except that it never modifies the errno variable.  Changed all references to sem_getvalue in the OS to nxsem_getvalue().

    sched/semaphore:  Rename all internal private functions from sem_xyz to nxsem_xyz.  The sem_ prefix is (will be) reserved only for the application semaphore interfaces.

    libc/semaphore:  Add nxsem_init() which is identical to sem_init() except that it never modifies the errno variable.  Changed all references to sem_init in the OS to nxsem_init().

    sched/semaphore:  Rename sem_tickwait() to nxsem_tickwait() so that it is clear this is an internal OS function.

    sched/semaphoate:  Rename sem_reset() to nxsem_reset() so that it is clear this is an internal OS function.
This commit is contained in:
Gregory Nutt
2017-10-03 12:51:15 -06:00
parent 2997a49e51
commit 83cdb0c552
328 changed files with 895 additions and 792 deletions
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include/nuttx/semaphore.h
+74 -13
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@@ -1,7 +1,7 @@
/****************************************************************************
* include/nuttx/semaphore.h
*
* Copyright (C) 2014-2016 Gregory Nutt. All rights reserved.
* Copyright (C) 2014-2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
@@ -98,7 +98,34 @@ extern "C"
****************************************************************************/
/****************************************************************************
* Name: sem_tickwait
* Name: nxsem_init
*
* Description:
* This function initializes the UNAMED semaphore sem. Following a
* successful call to nxsem_init(), the semaphore may be used in subsequent
* calls to sem_wait(), sem_post(), and sem_trywait(). The semaphore
* remains usable until it is destroyed.
*
* Only sem itself may be used for performing synchronization. The result
* of referring to copies of sem in calls to sem_wait(), sem_trywait(),
* sem_post(), and sem_destroy() is undefined.
*
* Parameters:
* sem - Semaphore to be initialized
* pshared - Process sharing (not used)
* value - Semaphore initialization value
*
* Return Value:
* This is an internal OS interface and should not be used byapplications.
* It follows the NuttX internal error return policy: Zero (OK) is
* returned on success. A negated errno value is returned on failure.
*
****************************************************************************/
int nxsem_init(FAR sem_t *sem, int pshared, unsigned int value);
/****************************************************************************
* Name: nxsem_tickwait
*
* Description:
* This function is a lighter weight version of sem_timedwait(). It is
@@ -115,19 +142,49 @@ extern "C"
* to sem_trywait().
*
* Return Value:
* Zero (OK) is returned on success. A negated errno value is returned on
* failure. -ETIMEDOUT is returned on the timeout condition.
* This is an internal OS interface, not available to applications, and
* hence follows the NuttX internal error return policy: Zero (OK) is
* returned on success. A negated errno value is returned on failure.
* -ETIMEDOUT is returned on the timeout condition.
*
****************************************************************************/
int sem_tickwait(FAR sem_t *sem, systime_t start, uint32_t delay);
int nxsem_tickwait(FAR sem_t *sem, systime_t start, uint32_t delay);
/****************************************************************************
* Name: sem_reset
* Name: nxsem_getvalue
*
* Description:
* This function updates the location referenced by 'sval' argument to
* have the value of the semaphore referenced by 'sem' without effecting
* the state of the semaphore. The updated value represents the actual
* semaphore value that occurred at some unspecified time during the call,
* but may not reflect the actual value of the semaphore when it is
* returned to the calling task.
*
* If 'sem' is locked, the value return by nxsem_getvalue() will either be
* zero or a negative number whose absolute value represents the number
* of tasks waiting for the semaphore.
*
* Parameters:
* sem - Semaphore descriptor
* sval - Buffer by which the value is returned
*
* Return Value:
* This is an internal OS interface and should not be used by applications.
* It follows the NuttX internal error return policy: Zero (OK) is
* returned on success. A negated errno value is returned on failure.
*
****************************************************************************/
int nxsem_getvalue(FAR sem_t *sem, FAR int *sval);
/****************************************************************************
* Name: nxsem_reset
*
* Description:
* Reset a semaphore count to a specific value. This is similar to part
* of the operation of sem_init(). But sem_reset() may need to wake up
* of the operation of nxsem_init(). But nxsem_reset() may need to wake up
* tasks waiting on a count. This kind of operation is sometimes required
* within the OS (only) for certain error handling conditions.
*
@@ -136,11 +193,13 @@ int sem_tickwait(FAR sem_t *sem, systime_t start, uint32_t delay);
* count - The requested semaphore count
*
* Return Value:
* 0 (OK) or a negated errno value if unsuccessful
* This is an internal OS interface, not available to applications, and
* hence follows the NuttX internal error return policy: Zero (OK) is
* returned on success. A negated errno value is returned on failure.
*
****************************************************************************/
int sem_reset(FAR sem_t *sem, int16_t count);
int nxsem_reset(FAR sem_t *sem, int16_t count);
/****************************************************************************
* Name: sem_getprotocol
@@ -155,8 +214,9 @@ int sem_reset(FAR sem_t *sem, int16_t count);
* value.
*
* Return Value:
* 0 if successful. Otherwise, -1 is returned and the errno value is set
* appropriately.
* This function is exposed as a non-standard application interface. It
* returns zero (OK) if successful. Otherwise, -1 (ERROR) is returned and
* the errno value is set appropriately.
*
****************************************************************************/
@@ -193,8 +253,9 @@ int sem_getprotocol(FAR sem_t *sem, FAR int *protocol);
* protocol - The new protocol to use
*
* Return Value:
* 0 if successful. Otherwise, -1 is returned and the errno value is set
* appropriately.
* This function is exposed as a non-standard application interface. It
* returns zero (OK) if successful. Otherwise, -1 (ERROR) is returned and
* the errno value is set appropriately.
*
****************************************************************************/