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is a pointer to a variable that holds an error code:
OS_ERR_NONE
if If a memory block is available and returned to the application.
OS_ERR_MEM_INVALID_P_BLK
if If OS_CFG_ARG_CHK_EN is set to 1 in os_cfg.h: if the user passed a NULL pointer for the memory block being returned to the memory partition.
OS_ERR_MEM_INVALID_P_MEM
if If OS_CFG_ARG_CHK_EN is set to 1 in os_cfg.h: if p_mem is a NULL pointer.
OS_ERR_MEM_MEM_FULL
if If returning a memory block to an already full memory partition. This would indicate that the user freed more blocks that were allocated and potentially did not return some of the memory blocks to the proper memory partition.
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