shmop.2 (2010 09)

shmop(2) shmop(2)

[EACCES] Operation permission is denied to the calling process.

[EINVAL] shmid is not a valid shared memory identiﬁer, (possibly because the shared memory

segment was already removed using shmctl (2) with

IPC_RMID), or the calling pro-

cess is already attached to shmid.

[EINVAL] shmaddr is not zero and the machine does not permit nonzero values, or shmaddr is

not equal to the current attach location for the shared memory segment.

[ENOMEM] The available data space is not large enough to accommodate the shared memory

segment.

[EMFILE] The number of shared memory segments attached to the calling process exceed the

system-imposed limit.

shmdt() fails, errno is set to one of the following values.

[EINVAL] shmaddr is not the data segment start address of a shared memory segment.

EXAMPLES

The following call to

shmat() attaches the shared memory segment to the process. This example

assumes the process has a valid shmid , which can be obtained by calling shmget (2).

char *shmptr;

shmptr = (char *) shmat(myshmid, 0, 0);

The following call to shmdt() then detaches the shared memory segment.

shmdt (shmptr);