CDMmap (FUN)ΒΆ

FUNCTION CDMmap : POINTER TO BYTE

Map files or devices into memory. mmap() creates a new mapping in the virtual address space of the calling process.

InOut:

Scope

Name

Type

Comment

Return

CDMmap

POINTER TO BYTE

pointer to the mapped area, or MAP_FAILED if failed.

Input

addr

POINTER TO BYTE

Pointer to starting address for the new mapping

length

UDINT

Number of bytes mapped

prot

DINT
Memory protection of the mapping. It is either PROT_NONE or the bitwise OR of one or more of the following flags:

  • PROT_EXEC: Pages may be executed

  • PROT_READ: Pages may be read

  • PROT_WRITE: Pages may be written

  • PROT_NONE: Pages may not be accessed

flags

DINT
one of the following flags

  • MAP_SHARED: Share this mapping

  • MAP_SHARED_VALIDATE: This flag provides the same behavior as MAP_SHARED except that MAP_SHARED mappings ignore unknown flags in flags

  • MAP_PRIVATE: Create a private copy-on-write mapping

Optional flags for mmap: See linux man page for Details

hFile

RTS_IEC_HANDLE

File descriptor of the file to be mapped

offset

DINT

Offset in the file (or other object) where mapping starts

pResult

POINTER TO DINT

Pointer to linux errno error code, 0 is ok