T-Kernel Specification (1.B0.02)

214 CHAPTER 4. T-KERNEL/OS FUNCTIONS
tk cre res
Create Resource Group
[C Language Interface]
ID resid = tk_cre_res ( ) ;
[Parameters]
None
[Return Parameters]
ID resid Resource ID
or Error Code
[Error Codes]
E OK
E LIMIT
E NOMEM
Normal completion
Number of resource groups exceeds the system limit
Insufficient memory (memory for control block cannot be allocated)
[Description]
Creates a new resource group, assigning to it a resource control block and resource ID.
Resource IDs are assigned in common for the entire system. A separate resource control block is created
for each subsystem (see Figure 4.15).
Resource ID
#1 #2 #3
Subsystem A
Subsystem B
Subsystem C
ResBlk ResBlk ResBlk
ResBlk ResBlk ResBlk
ResBlk ResBlk ResBlk
Figure 4.15: Subsystems and Resource Groups
In some cases a new subsystem will be defined when a resource group is already created. Even in such
a case, it is necessary to create a resource control block of an already existing resource group for the
newly registered subsystem. In other words, there may be cases where resource control block creation
must be performed by tk def ssy. For example, if a new subsystem ID is defined in a situation like that
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T-Kernel 1.B0.02