Function linuxcnc_hal_sys::rtapi_shmem_new

pub unsafe extern "C" fn rtapi_shmem_new(
    key: c_int, 
    module_id: c_int, 
    size: c_ulong
) -> c_int

'rtapi_shmem_new()' allocates a block of shared memory. 'key' identifies the memory block, and must be non-zero. All modules wishing to access the same memory must use the same key. 'module_id' is the ID of the module that is making the call (see rtapi_init). The block will be at least 'size' bytes, and may be rounded up. Allocating many small blocks may be very wasteful. When a particular block is allocated for the first time, the first 4 bytes are zeroed. Subsequent allocations of the same block by other modules or processes will not touch the contents of the block. Applications can use those bytes to see if they need to initialize the block, or if another module already did so. On success, it returns a positive integer ID, which is used for all subsequent calls dealing with the block. On failure it returns a negative error code. Call only from within user or init/cleanup code, not from realtime tasks.