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Text File  |  2002-10-03  |  3.2 KB  |  67 lines
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  4. ccccppppsssseeeemmmmaaaa((((DDDD3333XXXX))))                                                        ccccppppsssseeeemmmmaaaa((((DDDD3333XXXX))))
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  8. NNNNAAAAMMMMEEEE
  9.      _cccc_pppp_ssss_eeee_mmmm_aaaa - conditionally perform a "P" 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.      _iiii_nnnn_tttt _cccc_pppp_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 _cccc_pppp_ssss_eeee_mmmm_aaaa to conditionally
  20.           decrement.
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  22. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  23.      _cccc_pppp_ssss_eeee_mmmm_aaaa conditionally performs a "P" operation depending on the current
  24.      value of the semaphore. If the semaphore value is less than or equal to
  25.      0, _cccc_pppp_ssss_eeee_mmmm_aaaa returns without altering the semaphore. Otherwise, _cccc_pppp_ssss_eeee_mmmm_aaaa
  26.      decrements the semaphore value by 1 and returns. _cccc_pppp_ssss_eeee_mmmm_aaaa effectively
  27.      performs a "P" operation if it does not cause the process to sleep;
  28.      otherwise, it simply returns. To initialize semaphores before using them,
  29.      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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  31.    RRRReeeettttuuuurrrrnnnn VVVVaaaalllluuuueeeessss
  32.      _cccc_pppp_ssss_eeee_mmmm_aaaa returns 0 if the semaphore value is less than or equal to 0. (If
  33.      _cccc_pppp_ssss_eeee_mmmm_aaaa returns 0, _pppp_ssss_eeee_mmmm_aaaa(D3X) would have slept.) Otherwise _cccc_pppp_ssss_eeee_mmmm_aaaa returns
  34.      1.
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  36.    SSSSeeeeeeee AAAAllllssssoooo
  37.      _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), _pppp_ssss_eeee_mmmm_aaaa(D3X), _SSSS_LLLL_EEEE_EEEE_PPPP______TTTT_RRRR_YYYY_LLLL_OOOO_CCCC_KKKK(D3)
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  63.                                                                         PPPPaaaaggggeeee 1111
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