Search results
Results from the WOW.Com Content Network
The C programming language manages memory statically, automatically, or dynamically.Static-duration variables are allocated in main memory, usually along with the executable code of the program, and persist for the lifetime of the program; automatic-duration variables are allocated on the stack and come and go as functions are called and return.
An example of the latter is found in the Commodore 64, which uses a form of memory mapping to cause RAM or I/O hardware to appear in the 0xD000–0xDFFF range. Port-mapped I/O often uses a special class of CPU instructions designed specifically for performing I/O, such as the in and out instructions found on microprocessors based on the x86 ...
File-backed mapping maps an area of the process's virtual memory to files; that is, reading those areas of memory causes the file to be read. It is the default mapping type. Anonymous mapping maps an area of the process's virtual memory not backed by any file, made available via the MAP_ANONYMOUS/MAP_ANON flags.
Memory-mapped I/O, an alternative to port I/O; a communication between CPU and peripheral device using the same instructions, and same bus, as between CPU and memory; Virtual memory, technique which gives an application program the impression that it has contiguous working memory, while in fact it is physically fragmented and may even overflow ...
In virtual memory implementations and memory management units, a memory map refers to page tables or hardware registers, which store the mapping between a certain process's virtual memory layout and how that space relates to physical memory addresses. In native debugger programs, a memory map refers to the mapping between loaded executable(or ...
A memory-mapped file is a segment of virtual memory [1] that has been assigned a direct byte-for-byte correlation with some portion of a file or file-like resource. This resource is typically a file that is physically present on disk, but can also be a device, shared memory object, or other resource that an operating system can reference through a file descriptor.
Alignment concerns can affect areas much larger than a C structure when the purpose is the efficient mapping of that area through a hardware address translation mechanism (PCI remapping, operation of a MMU). For instance, on a 32-bit operating system, a 4 KiB (4096 bytes) page is not just an arbitrary 4 KiB chunk of data. Instead, it is usually ...
In response to this, many modern high-level computer languages (for example Java) do not permit direct access to memory using addresses. Also, the safe C dialect Cyclone addresses many of the issues with pointers. See C programming language for more discussion. The void pointer, or void*, is supported in ANSI C and C++ as a generic pointer type.