dmd.root.rmem

Allocate memory using malloc or the GC depending on the configuration.

Authors

Walter Bright, http://www.digitalmars.com

License

Boost License 1.0

Source: root/rmem.d

Documentation: https://dlang.org/phobos/dmd_root_rmem.html

Coverage: https://codecov.io/gh/dlang/dmd/src/master/src/dmd/root/rmem.d

  • pureMalloc

    Declaration

    pure nothrow @nogc @trusted void* pureMalloc(size_t size);
    pure nothrow @nogc @trusted void* pureCalloc(size_t nmemb, size_t size);
    pure nothrow @nogc @system void* pureRealloc(void* ptr, size_t size);
    pure nothrow @nogc @system void pureFree(void* ptr);

    Pure variants of C's memory allocation functions malloc, calloc, and realloc and deallocation function free.

    Discussion

    UNIX 98 requires that errno be set to ENOMEM upon failure. https://linux.die.net/man/3/malloc However, this is irrelevant for DMD's purposes, and best practice protocol for using errno is to treat it as an out parameter, and not something with state that can be relied on across function calls. So, we'll ignore it.

    See Also

    D's rules for purity, which allow for memory allocation under specific circumstances.

  • xarraydup

    Declaration

    pure nothrow char[] xarraydup(const(char)[] s);

    Makes a null-terminated copy of the given string on newly allocated memory. The null-terminator won't be part of the returned string slice. It will be at position n where n is the length of the input string.

    Parameters

    const(char)[] s

    string to copy

    Return Value

    A null-terminated copy of the input array.

    Examples

    1. auto s1 = "foo"; auto s2 = s1.xarraydup; s2[0] = 'b'; assert(s1 == "foo"); assert(s2 == "boo"); assert(*(s2.ptr + s2.length) == '\0'); string sEmpty; assert(sEmpty.xarraydup is null);

  • arraydup

    Declaration

    pure nothrow T[] arraydup(T)(scope const T[] s);

    Makes a copy of the given array on newly allocated memory.

    Parameters

    T[] s

    array to copy

    Return Value

    A copy of the input array.

    Examples

    1. auto s1 = [0, 1, 2]; auto s2 = s1.arraydup; s2[0] = 4; assert(s1 == [0, 1, 2]); assert(s2 == [4, 1, 2]); string sEmpty; assert(sEmpty.arraydup is null);

  • Pool

    Declaration

    struct Pool(T) if (is(T == class));

    Defines a pool for class objects. Objects can be fetched from the pool with make() and returned to the pool with dispose(). Using a reference that has been dispose()d has undefined behavior. make() may return memory that has been previously dispose()d.

    Discussion

    Currently the pool has effect only if the GC is NOT used (i.e. either version(GC) or mem.isGCEnabled is false). Otherwise make just forwards to new and dispose does nothing.

    Internally the implementation uses a singly-linked freelist with a global root. The "next" pointer is stored in the first word of each disposed object.

    • make

      Declaration

      T make(string f = __FILE__, uint l = __LINE__, A...)(auto ref A args);

      Returns a reference to a new object in the same state as if created with new T(args).

    • dispose

      Declaration

      void dispose(string f = __FILE__, uint l = __LINE__, A...)(T goner);

      Signals to the pool that this object is no longer used, so it can recycle its memory.