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/ IRIX Base Documentation 2001 May / SGI IRIX Base Documentation 2001 May.iso / usr / share / catman / p_man / catD / cvsema.z / cvsema
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Text File  |  1998-10-30  |  2.8 KB  |  67 lines
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  4. ccccvvvvsssseeeemmmmaaaa((((DDDD3333XXXX))))                                                        ccccvvvvsssseeeemmmmaaaa((((DDDD3333XXXX))))
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  8. NNNNAAAAMMMMEEEE
  9.      _cccc_vvvv_ssss_eeee_mmmm_aaaa - conditionally perform a "V" or wait semaphore operation
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  11. SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
  12.      _####_iiii_nnnn_cccc_llll_uuuu_dddd_eeee _""""_ssss_yyyy_ssss_////_tttt_yyyy_pppp_eeee_ssss_...._hhhh_""""
  13.      _####_iiii_nnnn_cccc_llll_uuuu_dddd_eeee _""""_ssss_yyyy_ssss_////_ssss_eeee_mmmm_aaaa_...._hhhh_""""
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  15.      _cccc_vvvv_ssss_eeee_mmmm_aaaa_((((_ssss_eeee_mmmm_aaaa______tttt _****_s_e_m_a_p_))))_;;;;
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  17.    AAAArrrrgggguuuummmmeeeennnnttttssss
  18.      _s_e_m_a_p
  19.           Expects a pointer to the semaphore you want to conditionally.
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  21. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  22.      _cccc_vvvv_ssss_eeee_mmmm_aaaa routine conditionally performs a "V" operation depending on the
  23.      current value of the semaphore. If the semaphore value is strictly less
  24.      than 0, _cccc_vvvv_ssss_eeee_mmmm_aaaa increments the semaphore value by 1 and wakes up a
  25.      sleeping process.  Otherwise, _cccc_vvvv_ssss_eeee_mmmm_aaaa simply returns. _cccc_vvvv_ssss_eeee_mmmm_aaaa effectively
  26.      performs a "V" operation if there is a process asleep on the semaphore;
  27.      otherwise, it does nothing. To initialize semaphores before you use them,
  28.      call _iiii_nnnn_iiii_tttt_nnnn_ssss_eeee_mmmm_aaaa(D3X) or _iiii_nnnn_iiii_tttt_nnnn_ssss_eeee_mmmm_aaaa______mmmm_uuuu_tttt_eeee_xxxx(D3X).
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  30.    RRRReeeettttuuuurrrrnnnn VVVVaaaalllluuuueeeessss
  31.      _cccc_vvvv_ssss_eeee_mmmm_aaaa returns 1 if the semaphore value is less than 0 and a process is
  32.      awakened. Otherwise _cccc_vvvv_ssss_eeee_mmmm_aaaa returns 0.
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  34.    SSSSeeeeeeee AAAAllllssssoooo
  35.      _iiii_nnnn_iiii_tttt_nnnn_ssss_eeee_mmmm_aaaa(D3X), _iiii_nnnn_iiii_tttt_nnnn_ssss_eeee_mmmm_aaaa______mmmm_uuuu_tttt_eeee_xxxx(D3X), _vvvv_ssss_eeee_mmmm_aaaa(D3X)
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  63.                                                                         PPPPaaaaggggeeee 1111
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