dshm_attach(DSHM)

dshm_attach -- attach DSHM segment

Synopsis

   #include <dshm.h>
   
   dshm_handle_t	dshm_attach (int dshmid, int dshmflgs, unsigned long * max_mappings);

Description

dshm_attach attaches the designated DSHM segment to the calling process, placing the map at the logical address assigned by dshm_get(DSHM), and allocating and initializing the per-attach management data.

Upon successful return, *max_mappings indicates the maximum concurrent mappings the application can safely use (total across all attached processes) without deadlocking.

Return values

If dshm_attach returns DSHM_NULL_HANDLE, an error occurred. errno is set to identify the error.

Otherwise, dshm_attach returns an opaque handle for use in subsequent operations on the attached segment.

Errors

In the following conditions, dshm_attach fails and sets errno to:

EBUSY: Segment is not initialized. Initialization (by dshm_get(DSHM)) is still in progress or was terminated prematurely.
EINVAL: Illegal flags in dshmflgs.
EINVAL: Attach failed due to address space conflict.
ENOMEM: Insufficient resources to allocate per-attach management structure(s).
EINVAL: dshmid is not a valid dynamically mapped shared memory identifier.
EACCES: Operation permission is denied to the calling process.
ENOMEM: The available data space is not large enough to accommodate the shared memory segment.
EMFILE: The number of dynamically mapped shared memory segments attached to the calling process would exceed the system-imposed limit.

References

dshm_alignment(DSHM), dshm_bufindex(DSHM), dshm_control(DSHM), dshm_detach(DSHM), dshm_get(DSHM), dshm_map(DSHM), dshm_minmapsize(DSHM), dshm_reattach(DSHM), dshm_unmap(DSHM), dshm_updatetlb(DSHM)