mem

mem examples

Two steps that introduce the CWIST memory API declared in include/cwist/core/mem/alloc.h and include/cwist/core/mem/gc.h. Both are console programs — they print to stdout and exit.

Step	Shows
step-1-alloc	cwist_alloc, cwist_realloc, cwist_strdup, cwist_strndup, and cwist_alloc_array
step-2-gc	epoch-based garbage collection with cwist_gc, cwist_reg_ptr, cwist_reg_ptr_sized, cwist_gc_rotate, and cwist_gc_shutdown

Build

Build the library first, from the repository root:

make

Then build each step (both ship their own Makefile):

make -C example/mem/step-1-alloc
make -C example/mem/step-2-gc

make examples-check also builds both.

Run

Step 1: allocation

./example/mem/step-1-alloc/step-1-alloc

Walks through the five allocation helpers. cwist_alloc returns zeroed memory, cwist_realloc grows an existing block in place, cwist_strdup / cwist_strndup copy strings, and cwist_alloc_array(count, size) allocates a zeroed array. Everything is released with cwist_free:

=== Memory Allocation Tutorial ===

[cwist_alloc]
buf: 'Hello from cwist_alloc!'

[cwist_realloc]
buf after realloc: 'Hello from cwist_alloc! (resized)'

[cwist_strdup / cwist_strndup]
strdup:  'Duplicate me!'
strndup: 'Duplicate'

[cwist_alloc_array]
arr: 10 20 30 40 50 60 70 80

=== Done ===

Step 2: epoch GC

./example/mem/step-2-gc/step-2-gc

Initialises a GC context with manual rotation (cwist_gc(&gc, /*manual_rotation=*/true)), registers three cwist_alloc'd buffers with cwist_reg_ptr / cwist_reg_ptr_sized, and rotates the epoch with cwist_gc_rotate between allocations. Registration hands ownership to the context: an explicit cwist_free (p1) detaches its block from the context automatically, and cwist_gc_shutdown releases every block still registered (p2, p3) with cwist_free:

=== Epoch GC Tutorial ===
GC initialized (manual rotation mode)

[Register pointers]
Registered p1 (256 B) and p2 (512 B)

[Manual rotation]
Epoch rotated
Explicitly freed p1 (auto-unregistered)
Registered p3 (1024 B)
Second rotation complete

[Shutdown]
GC shut down (p2 and p3 reclaimed)

=== Done ===

Clean

make -C example/mem/step-1-alloc clean
make -C example/mem/step-2-gc clean