Description
Obtains a memory block from a memory partition. It is assumed that the application knows the size of each memory block obtained. Also, the application must return the memory block [using OSMemPut()] to the same memory partition when it no longer requires it. OSMemGet() may be called more than once until all memory blocks are allocated.
Files
os.h/os_mem.c
Prototype
Arguments
p_mem
is a pointer to the desired memory partition control block.
p_err
is a pointer to a variable that holds an error code:
OS_ERR_NONE
If a memory block is available and returned to the application.
OS_ERR_MEM_INVALID_P_MEM
If OS_CFG_ARG_CHK_EN is set to DEF_ENABLED in os_cfg.h: if p_mem is a NULL pointer.
OS_ERR_MEM_NO_FREE_BLKS
If the memory partition does not contain additional memory blocks to allocate.
OS_ERR_OBJ_TYPE
If OS_CFG_OBJ_TYPE_CHK_EN is set to DEF_ENABLED in os_cfg.h: if the user did not pass a pointer to a memory partition.
Returned Value
OSMemGet() returns a pointer to the allocated memory block if one is available. If a memory block is not available from the memory partition, OSMemGet() returns a NULL pointer. It is up to the application to “cast” the pointer to the proper data type since OSMemGet() returns a void *.
Required Configuration
OS_CFG_MEM_EN must be enabled in os_cfg.h. Refer to µC-OS-III Configuration Manual,
Callers
Application and ISRs.
Notes/Warnings
- Memory partitions must be created before they are used.