mmap2 - map files or devices into memory
#include <sys/mman.h>
void *mmap2(void *addr, size_t length, int prot,
int flags, int fd, off_t 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 appropriately.
- 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)