mlock(3C)

mlock -- lock pages in memory

Synopsis

   #include <sys/types.h>
   #include <sys/mman.h>
   
   int mlock(void *addr, size_t len);
   

   int munlock(void *addr, size_t len);

The function mlock uses the mappings established for the address range

   [addr, addr + len)

to identify pages to be locked in memory. The effect of

   mlock(addr, len)

is equivalent to

   memcntl(addr, len, MC_LOCK, 0, 0, 0)

munlock removes locks established with mlock. The effect of

   munlock(addr, len)

is equivalent to

   memcntl(addr, len, MC_UNLOCK, 0, 0, 0)

Locks established with mlock are not inherited by a child process after a fork and are not nested.

Upon successful completion, the functions mlock and munlock return 0; otherwise, they return -1 and set errno to indicate the error.

Use of mlock and munlock requires that the user have appropriate privileges.