mlockall(S)

mlockall -- lock address space

Synopsis

   #include <sys/mman.h>
   
   int mlockall(int flags);
   

   int munlockall(void);

Description

The function mlockall causes all pages mapped by an address space to be locked in memory. The effect of

   mlockall(flags)

is equivalent to:

   memcntl(0, 0, MC_LOCKAS, flags, 0, 0)

The value of flags determines whether the pages to be locked are those currently mapped by the address space, those that will be mapped in the future, or both:

MCL_CURRENT: Lock current mappings
MCL_FUTURE: Lock future mappings

The function munlockall removes address space locks and locks on mappings in the address space. The effect of munlockall is equivalent to:

   memcntl(0, 0, MC_UNLOCKAS, 0, 0, 0)

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

Return values

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

References

fork(S), memcntl(S), mlock(S), mmap(S), plock(S), sysconf(S)

Notices

Use of mlockall and munlockall requires that the user have appropriate privileges.