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Open a binary file as a read-only mmap-backed vector.

Source: R/altrep.R
mmap_real.Rd

mmap_real opens a file of IEEE 754 doubles, mmap_int opens int32, mmap_lgl opens int32 interpreted as R logicals. length is the element count; the file must contain at least length * sizeof(element) bytes.

Usage

mmap_real(path, length)

mmap_int(path, length)

mmap_lgl(path, length)

Arguments

path

Path to the binary file.

length

Number of elements to map.

Value

An ALTREP-backed R vector sharing the file's memory.

Details

Length is passed through as double to accommodate R_xlen_t; values above 2^53 lose precision. Pass only integer-valued doubles.

Examples

f <- tempfile(fileext = ".bin")
writeBin(c(1.5, 2.5, 3.5), f)
v <- mmap_real(f, 3L)
v[]
#> [1] 1.5 2.5 3.5
unlink(f)