write_byte

Builtin index · File I/O

write_byte(f, b)

Input: f, b · Output: no output

What it is

Writes one raw byte to f (file handle, opened writable/appendable). b (number) must be in 0..=255, or the call errors.

Overloads

One call shape — this function is not overloaded.

Code	Input	Output	Description
`write_byte(f, b)`	`f` —Writes one raw byte to `f` (file handle, opened writable/appendable). `b` number`b` (number) must be in `0..=255`, or the call errors.	no output	—

Examples

From the documentation, and run by the build -- the output and the figure below are what the engine actually produced. Simplest first.

f = fopen("mmap_demo.bin", "wb")
write_byte(f, 65)
write_byte(f, 66)
write_byte(f, 67)
write_byte(f, 68)
write_byte(f, 69)
write_byte(f, 70)
write_byte(f, 71)
write_byte(f, 72)
close(f)

m = mmap_open("mmap_demo.bin")
n = mmap_len(m)
first4 = mmap_read(m, 0, 4)
last4 = mmap_read(m, 4, 4)
print("n = {n}")
print("first4 = {first4}")
print("last4 = {last4}")

from tour

How it works

write_byte(f, b) — one raw byte, 0-255.

From the note above this builtin in the interpreter, where the reasoning was written down as it was built.