RTEMS 4.8.1 On-Line Library

Semaphore Manager T_CSEM Structure

RTEMS ITRON 3.0 API User's Guide

3.2.2: T_CSEM Structure

The T_CSEM structure is used to define the characteristics of a semaphore and passed an as argument to the cre_sem service. The structure is defined as follows:

/*
 *  Create Semaphore (cre_sem) Structure
 */

typedef struct t_csem {
  VP    exinf;    /* extended information */
  ATR   sematr;   /* semaphore attributes */
  /* Following is the extended function for [level X]. */
  INT   isemcnt;   /* initial semaphore count */
  INT   maxsem;    /* maximum semaphore count */
  /* additional implementation dependent information may be included */
} T_CSEM;

/*
 *  sematr - Semaphore Attribute Values
 */

#define TA_TFIFO   0x00   /* waiting tasks are handled by FIFO */
#define TA_TPRI    0x01   /* waiting tasks are handled by priority */

where the meaning of each field is:

exinf: is for any extended information that the implementation may define. This implementation does not use this field.
sematr: is the attributes for this semaphore. The only attributed which can be specified is whether tasks wait in FIFO (TA_TFIFO) or priority (TA_TPRI) order.
isemcnt: is the initial count of the semaphore.
maxsem: is the maximum count the semaphore may have. It places an upper limit on the value taken by the semaphore.

RTEMS ITRON 3.0 API User's Guide