Manpages - mmap2.2

mmap2 - map files or devices into memory

  #include <sys/mman.h> /* Definition of MAP_* and PROT_* constants */
  #include <sys/syscall.h> /* Definition of SYS_* constants */
  "#include<unistd.h>

  void *syscall(SYS_mmap2, unsigned long addr, unsigned long length,
   unsigned long prot, unsigned long flags,
   unsigned long fd, unsigned long pgoffset);

This is probably not the system call that you are interested in; instead, see *mmap*(2), which describes the glibc wrapper function that invokes this system call.

The *mmap2*() system call provides the same interface as *mmap*(2), except that the final argument specifies the offset into the file in 4096-byte units (instead of bytes, as is done by *mmap*(2)). This enables applications that use a 32-bit off_t to map large files (up to 2^44 bytes).

On success, *mmap2*() returns a pointer to the mapped area. On error, -1 is returned and errno is set to indicate the error.

EFAULT

Problem with getting the data from user space.

EINVAL

(Various platforms where the page size is not 4096 bytes.) offset * 4096 is not a multiple of the system page size.

*mmap2*() can also return any of the errors described in *mmap*(2).

*mmap2*() is available since Linux 2.3.31.

This system call is Linux-specific.

On architectures where this system call is present, the glibc *mmap*() wrapper function invokes this system call rather than the *mmap*(2) system call.

This system call does not exist on x86-64.

On ia64, the unit for offset is actually the system page size, rather than 4096 bytes.

*getpagesize*(2), *mmap*(2), *mremap*(2), *msync*(2), *shm_open*(3)

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