T-Kernel Specification (1.B0.02)

4.4. SYNCHRONIZATION AND COMMUNICATION FUNCTIONS 87
tk cre flg
Create Event Flag
[C Language Interface]
ID flgid = tk_cre_flg ( T_CFLG *pk_cflg ) ;
[Parameters]
T CFLG* pk cflg Information about the event flag to be created
pk cflg detail:
VP exinf Extended information
ATR flgatr Event flag attributes
UINT iflgptn Initial event flag pattern
(Other implementation-dependent parameters may be added beyond this point.)
[Return Parameters]
ID flgid Event flag ID
or Error Code
[Error Codes]
E OK
E NOMEM
E LIMIT
E RSATR
E PAR
Normal completion
Insufficient memory (memory for control block cannot be allocated)
Number of event flags exceeds the system limit
Reserved attribute (flgatr is invalid or cannot be used)
Parameter error (pk cflg is invalid)
[Description]
Creates an event flag, assigning to it an event flag ID.
This system call allocates a control block to the created event flag and sets its initial value to iflgptn.
An event flag handles one word’s worth of bits as a group. All operations are performed in single word
units.
exinf can be used freely by the user to set miscellaneous information about the created event flag.
The information set in this parameter can be referenced by tk ref flg. If a larger area is needed for
indicating user information, or if the information may need to be changed after the event flag is created,
this can be done by allocating separate memory for this purpose and putting the memory packet address
in exinf. The OS pays no attention to the contents of exinf.
flgatr indicates system attributes in its low bits and implementation-dependent information in the
high bits. Designation in the system attributes part of flgatr is as follows.
Copyright c○ 2002, 2003 by T-Engine Forum
T-Kernel 1.B0.02