pw_malloc#
Replacement interface for standard libc dynamic memory operations
Stable C C++
This module defines an interface for replacing the standard libc dynamic memory operations.
This facade doesn’t implement any heap structure or dynamic memory methods. It
only requires that backends implements pw::malloc::GetSystemAllocator
and
optionally pw::malloc::InitSystemAllocator
. These functions are called
before static initialization, and are responsible for initializing global data
structures required by the malloc
implementation.
The intent of this module is to provide an interface for user-provided dynamic memory operations that is compatible with different implementations.
Setup#
This module requires the following setup:
Choose a
pw_malloc
backend, or write one yourself.Select a backend in your build system. If using GN build, Specify the
pw_malloc_BACKEND
GN build arg to point to the library that provides apw_malloc
backend. If using the Bazel build, add the constraint value for the backend library that provides apw_malloc
backend.Add a dependency on the
pw_malloc
facade in your targetsexecutable
build template, e.g.:
template("platform_executable") {
target("executable", target_name) {
deps = []
config = []
forward_variables_from(invoker, "*")
if (pw_malloc_BACKEND != "") {
deps += [ dir_pw_malloc ]
}
}
}
Compile-time configuration#
This module has configuration options that globally affect the behavior of
pw_malloc
via compile-time configuration of this module.
See the module documentation for more details.
Heap initialization#
You can provide a region of memory to use as heap as either a byte span or a
pair of addresses to pw::malloc::InitSystemAllocator
.
Usage#
Once the heap is initialized, you may simply use malloc
and free
as you
would normally, as well as standard library functions like strdup
and
built-in routines like new
that use those functions.
If you configured a PW_MALLOC_METRICS_TYPE
, you can retrieve metrics using
pw::malloc::UpdateSystemMetrics()
.