noble (2) mmap2.2.gz

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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)