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Annotation of coherent/a/usr/man/COHERENT/shmget, revision 1.1.1.1

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                      3: shmget()               COHERENT System Call              shmget()
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                      8: Get shared-memory segment
                      9: 
                     10: #include <sys/shm.h>
                     11: sshhmmggeett(_k_e_y, _s_i_z_e, _s_h_m_f_l_g)
                     12: kkeeyy_tt _k_e_y; iinntt _s_i_z_e, _s_h_m_f_l_g;
                     13: 
                     14: shmget returns the shared-memory identifier associated with key.
                     15: 
                     16: A  shared-memory  identifier and  associated  data structure  and
                     17: shared memory  segment of size  size bytes is created  for key if
                     18: key does  not already have a  shared-memory identifier associated
                     19: with it, and (_s_h_m_f_l_g & IIPPCC_CCRREEAATT) is true.
                     20: 
                     21: Upon creation, the  data structure associated with the new shared
                     22: memory identifier is initialized as follows:
                     23: 
                     24: *  shm_perm.cuid,  shm_perm.uid, shm_perm.cgid,  and shm_perm.gid
                     25:    are set equal to the effective user ID and effective group ID,
                     26:    respectively, of the calling process.
                     27: 
                     28: *  The low-order nine bits  of shm_perm.mode are set equal to the
                     29:    low-order nine bits  of shmflg.  These nine bits define access
                     30:    permissions: the  top three bits give  the owner's access per-
                     31:    missions  (read, write,  execute), the  middle three  bits the
                     32:    owning group's access  permissions, and the low three bits ac-
                     33:    cess permissions for others.
                     34: 
                     35: *  shm_segsz is set equal to the value of size.
                     36: 
                     37: *  shm_lpid,  shm_nattch, shm_atime, and shm_dtime  are set equal
                     38:    to zero.  shm_ctime is set equal to the current time.
                     39: 
                     40: shmget fails if any of the following is true:
                     41: 
                     42: *  size  is less than the system-imposed  minimum or greater than
                     43:    the system-imposed maximum.  shmget sets errno to EINVAL.
                     44: 
                     45: *  A  shared-memory identifier exists for  key but operation per-
                     46:    mission  as specified  by the  low-order  nine bits  of shmflg
                     47:    would not be granted (EEAACCCCEESS).
                     48: 
                     49: *  A shared-memory identifier exists  for key but the size of the
                     50:    segment associated  with it is less than size  and size is not
                     51:    equal to zero (EEIINNVVAALL).
                     52: 
                     53: *  A shared-memory identifier  does not exist for key and (_s_h_m_f_l_g
                     54:    & IIPPCC_CCRREEAATT) is false (EENNOOEENNTT).
                     55: 
                     56: *  A shared-memory identifier is to be created but the system-im-
                     57:    posed  limit on  the maximum number  of allowed  shared memory
                     58:    identifiers system-wide would be exceeded (EENNOOSSPPCC).
                     59: 
                     60: *  A  shared-memory identifier and  associated shared-memory seg-
                     61:    ment are  to be created, but the  amount of available physical
                     62: 
                     63: 
                     64: COHERENT Lexicon                                           Page 1
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                     68: 
                     69: shmget()               COHERENT System Call              shmget()
                     70: 
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                     72: 
                     73:    memory is not sufficient to fill the request (EENNOOMMEEMM).
                     74: 
                     75: *   A shared-memory  identifier exists  for key  but (  (_s_h_m_f_l_g &
                     76:    IIPPCC_CCRREEAATT) && (_s_h_m_f_l_g & IIPPCC_EEXXCCLL) ) is true (EEEEXXIISSTT).
                     77: 
                     78: ***** Return Value *****
                     79: 
                     80: Upon successful completion,  shmget returns a shared-memory iden-
                     81: tifier, which  is always  a non-negative integer.   Otherwise, it
                     82: returns -1 and sets eerrrrnnoo to an appropriate value.
                     83: 
                     84: ***** Files *****
                     85: 
                     86: /usr/include/sys/ipc.h
                     87: /usr/include/sys/shm.h
                     88: /dev/shm
                     89: /drv/shm
                     90: 
                     91: ***** See Also *****
                     92: 
                     93: COHERENT system calls, shm, shmctl()
                     94: 
                     95: ***** Notes *****
                     96: 
                     97: To  improve  portability,  the  COHERENT  system  implements  its
                     98: shared-memory  functions as  a device  driver rather  than actual
                     99: system calls.
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                    130: COHERENT Lexicon                                           Page 2
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