Function diag_write_allocator_stats

src/foundation/diagnostics.c:189–222

}

static void diag_write_allocator_stats(void) {
    char flag[CBM_SZ_16];
    if (cbm_safe_getenv("CBM_MEM_STATS", flag, sizeof(flag), NULL) == NULL || flag[0] != '1') {
        return;
    }
    char path[CBM_PATH_MAX];
    /* Deliberately NOT inside the diagnostics directory: that tree is
     * owner-private with anchored (openat-based) writes on POSIX, which a plain
     * path-based open does not satisfy. This file is a developer diagnostic, so
     * a predictable temp path keeps it working identically on every platform —
     * diag_open_private_stats_file is what makes that path safe to write. */
    int written =
        snprintf(path, sizeof(path), "%s/cbm-allocator-stats-%d.txt", cbm_tmpdir(), (int)getpid());
    if (written <= 0 || (size_t)written >= sizeof(path)) {
        return;
    }
    FILE *sink = diag_open_private_stats_file(path);
    if (!sink) {
        return;
    }
    mi_stats_print_out(diag_stats_write, sink);
    /* Arena slice map: the legend distinguishes free-committed (retained, "_")
     * from free-reserved (already returned to the OS, ".") and free-purgeable
     * ("~"). That is what localises retained memory to a specific arena state
     * instead of inferring it from totals. mi_debug_show_arenas writes through
     * mimalloc's own output hook, so redirect that into this file. */
    (void)fputs("\n--- arenas ---\n", sink);
    mi_register_output(diag_stats_write, sink);
    mi_debug_show_arenas();
    mi_register_output(NULL, NULL);
    (void)fputs("\n--- options ---\n", sink);
    mi_options_print_out(diag_stats_write, sink);
    (void)fclose(sink);
}

static bool diag_set_output_paths(void) {
    int snapshot = snprintf(g_diag_path, sizeof(g_diag_path), "%s/%s", g_diag_directory_path,