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/ IRIX Base Documentation 2001 May / SGI IRIX Base Documentation 2001 May.iso / usr / share / catman / p_man / cat3c / makecontext.z / makecontext
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Text File  |  1998-10-20  |  6.2 KB  |  133 lines
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  4. mmmmaaaakkkkeeeeccccoooonnnntttteeeexxxxtttt((((3333CCCC))))                                                mmmmaaaakkkkeeeeccccoooonnnntttteeeexxxxtttt((((3333CCCC))))
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  8. NNNNAAAAMMMMEEEE
  9.      _mmmm_aaaa_kkkk_eeee_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt, _ssss_wwww_aaaa_pppp_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt - manipulate user contexts
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  11. SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
  12.      _####_iiii_nnnn_cccc_llll_uuuu_dddd_eeee _<<<<_uuuu_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt_...._hhhh_>>>>
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  14.      _vvvv_oooo_iiii_dddd _mmmm_aaaa_kkkk_eeee_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt _((((_uuuu_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt______tttt _****_u_c_p_,,,, _((((_vvvv_oooo_iiii_dddd_((((_****_))))_((((_))))_))))_f_u_n_c_,,,, _iiii_nnnn_tttt _a_r_g_c_,,,,_...._...._...._))))_;;;;
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  16.      _iiii_nnnn_tttt _ssss_wwww_aaaa_pppp_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt _((((_uuuu_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt______tttt _****_o_u_c_p_,,,, _uuuu_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt______tttt _****_u_c_p_))))_;;;;
  17.  
  18. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  19.      These functions are useful for implementing user-level context switching
  20.      between multiple threads of control within a process.
  21.  
  22.      _mmmm_aaaa_kkkk_eeee_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt modifies the context specified by _u_c_p, which has been
  23.      initialized using _gggg_eeee_tttt_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt; when this context is resumed using
  24.      _ssss_wwww_aaaa_pppp_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt or _ssss_eeee_tttt_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt [see _gggg_eeee_tttt_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt(2)], program execution
  25.      continues by calling the function _f_u_n_c, passing it the arguments that
  26.      follow _a_r_g_c in the _mmmm_aaaa_kkkk_eeee_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt call.  Before a call is made to
  27.      _mmmm_aaaa_kkkk_eeee_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt, the context being modified should have a stack allocated for
  28.      it.  The integer value of _a_r_g_c must match the number of arguments that
  29.      follow _a_r_g_c.  Otherwise the behavior is undefined.
  30.  
  31.      The _uuuu_cccc______llll_iiii_nnnn_kkkk field is used to determine the context that will be resumed
  32.      when the context being modified by _mmmm_aaaa_kkkk_eeee_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt returns. The _uuuu_cccc______llll_iiii_nnnn_kkkk field
  33.      should be initialized prior to the call to _mmmm_aaaa_kkkk_eeee_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt.
  34.  
  35.      _ssss_wwww_aaaa_pppp_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt saves the current context in the context structure pointed to
  36.      by _o_u_c_p and sets the context to the context structure pointed to by _u_c_p.
  37.  
  38.      These functions will fail if either of the following is true:
  39.  
  40.      _EEEE_NNNN_OOOO_MMMM_EEEE_MMMM         _u_c_p does not have enough stack left to complete the
  41.                     operation.
  42.  
  43.      _EEEE_FFFF_AAAA_UUUU_LLLL_TTTT         _u_c_p or _o_u_c_p points to an invalid address.
  44.  
  45. SSSSEEEEEEEE AAAALLLLSSSSOOOO
  46.      _eeee_xxxx_iiii_tttt(2), _gggg_eeee_tttt_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt(2), _ssss_iiii_gggg_aaaa_cccc_tttt_iiii_oooo_nnnn(2), _ssss_iiii_gggg_pppp_rrrr_oooo_cccc_mmmm_aaaa_ssss_kkkk(2), _uuuu_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt(5).
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  48. DDDDIIIIAAAAGGGGNNNNOOOOSSSSTTTTIIIICCCCSSSS
  49.      On successful completion, _ssss_wwww_aaaa_pppp_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt return a value of zero.  Otherwise,
  50.      a value of -1 is returned and _eeee_rrrr_rrrr_nnnn_oooo is set to indicate the error.
  51.  
  52. BBBBUUUUGGGGSSSS
  53.      Due to the procedure calling conventions on the MIPS processor and
  54.      restrictions of _ssss_tttt_dddd_aaaa_rrrr_gggg(5), the arguments that follow the _a_r_g_c parameter
  55.      for _mmmm_aaaa_kkkk_eeee_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt are restricted to longs and pointers only.
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  63.                                                                         PPPPaaaaggggeeee 1111
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  70. mmmmaaaakkkkeeeeccccoooonnnntttteeeexxxxtttt((((3333CCCC))))                                                mmmmaaaakkkkeeeeccccoooonnnntttteeeexxxxtttt((((3333CCCC))))
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  74. NOTES
  75.      The size of the _uuuu_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt______tttt structure may change in future releases.  To
  76.      remain binary compatible, users of these features must always use
  77.      _mmmm_aaaa_kkkk_eeee_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt or _gggg_eeee_tttt_cccc_oooo_nnnn_tttt_eeee_xxxx_tttt to create new instances of them.
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  129.                                                                         PPPPaaaaggggeeee 2222
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