mmap2(2)                      System Calls Manual                     mmap2(2)

NAME
       mmap2 - map files or devices into memory

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #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);

DESCRIPTION
       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).

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

ERRORS
       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).

VERSIONS
       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.

STANDARDS
       Linux.

HISTORY
       Linux 2.3.31.

SEE ALSO
       getpagesize(2), mmap(2), mremap(2), msync(2), shm_open(3)

Linux man-pages 6.7               2023-10-31                          mmap2(2)