core::arch::wasm32

Function memory_grow

1.33.0 · Source
pub fn memory_grow(const MEM: u32, delta: usize) -> usize
Available on WebAssembly and target_family="wasm" only.
Expand description

Corresponding intrinsic to wasm’s memory.grow instruction

This function, when called, will attempt to grow the default linear memory by the specified delta of pages. The current WebAssembly page size is 65536 bytes (64 KB). If memory is successfully grown then the previous size of memory, in pages, is returned. If memory cannot be grown then usize::MAX is returned.

The argument MEM is the numerical index of which memory to return the size of. Note that currently the WebAssembly specification only supports one memory, so it is required that zero is passed in. The argument is present to be forward-compatible with future WebAssembly revisions. If a nonzero argument is passed to this function it will currently unconditionally abort.