munmap(2)

NAME

     munmap - unmap pages of memory

SYNOPSIS

     #include <sys/mman.h>

     int munmap(void *addr, size_t len);

DESCRIPTION

     The munmap() function removes the mappings for pages in  the
     range  [addr,  addr  + len), rounding the len argument up to
     the  next  multiple  of  the  page  size  as   returned   by
     sysconf(3C).  If  addr is not the address of a mapping esta-
     blished by a prior call to mmap(2), the  behavior  is  unde-
     fined.  After  a  successful call to munmap() and before any
     subsequent mapping of the unmapped pages, further references
     to  these  pages  will result in the delivery of a SIGBUS or
     SIGSEGV signal to the process.

     The mmap(2) function often performs an implicit munmap().

RETURN VALUES

     Upon successful completion, munmap() returns  0;  otherwise,
     it returns -1 and sets errno to indicate an error.

ERRORS

     The munmap() function will fail if:

     EINVAL
           The  addr argument is not a multiple of the page  size
           as  returned  by  sysconf(3C);  addresses in the range
           [addr, addr + len) are outside the valid range for the
           address space of a process; or the  len argument has a
           value less than or equal to 0.

SEE ALSO

     mmap(2), sysconf(3C)