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SSSSIIIIGGGGSSSSEEEETTTT((((2222)))) SSSSIIIIGGGGSSSSEEEETTTT((((2222)))) NNNNAAAAMMMMEEEE sigset, sighold, sigrelse, sigignore, sigpause - signal management (System V) CCCC SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS ####iiiinnnncccclllluuuuddddeeee <<<<ssssiiiiggggnnnnaaaallll....hhhh>>>> _CCCC_:::: vvvvooooiiiidddd ((((****ssssiiiiggggsssseeeetttt ((((iiiinnnntttt ssssiiiigggg,,,, vvvvooooiiiidddd ((((****ddddiiiisssspppp))))(((())))))))))))(((())));;;; _CCCC_++++_++++_:::: vvvvooooiiiidddd ((((****ssssiiiiggggsssseeeetttt ((((iiiinnnntttt ssssiiiigggg,,,, vvvvooooiiiidddd ((((****ddddiiiisssspppp))))((((iiiinnnntttt))))))))))))((((iiiinnnntttt))));;;; _####_iiii_ffff ______XXXX_OOOO_PPPP_EEEE_NNNN______SSSS_OOOO_UUUU_RRRR_CCCC_EEEE vvvvooooiiiidddd ((((****ssssiiiiggggsssseeeetttt ((((iiiinnnntttt ssssiiiigggg,,,, vvvvooooiiiidddd ((((****ddddiiiisssspppp))))((((iiiinnnntttt))))))))))))((((iiiinnnntttt))));;;; _####_eeee_nnnn_dddd_iiii_ffff iiiinnnntttt ssssiiiigggghhhhoooolllldddd ((((iiiinnnntttt ssssiiiigggg))));;;; iiiinnnntttt ssssiiiiggggrrrreeeellllsssseeee ((((iiiinnnntttt ssssiiiigggg))));;;; iiiinnnntttt ssssiiiiggggiiiiggggnnnnoooorrrreeee ((((iiiinnnntttt ssssiiiigggg))));;;; iiiinnnntttt ssssiiiiggggppppaaaauuuusssseeee ((((iiiinnnntttt ssssiiiigggg))));;;; DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN These functions provide signal management for application processes. _ssss_iiii_gggg_ssss_eeee_tttt specifies the system signal action to be taken upon receipt of signal _s_i_g. _d_i_s_p specifies the signal's disposition, which may be _SSSS_IIII_GGGG______DDDD_FFFF_LLLL, _SSSS_IIII_GGGG______IIII_GGGG_NNNN, or the address of a signal handler. If _d_i_s_p is the address of a signal handler, the system adds _s_i_g to the calling process's signal mask before executing the signal handler; when the signal handler returns, the system restores the calling process's signal mask to its state prior to the delivery of the signal. In addition, if _d_i_s_p is equal to _SSSS_IIII_GGGG______HHHH_OOOO_LLLL_DDDD, _s_i_g is added to the calling process's signal mask and the signal's disposition remains unchanged. If _d_i_s_p is not equal to _SSSS_IIII_GGGG______HHHH_OOOO_LLLL_DDDD, _s_i_g will be removed from the calling process's signal mask (this behavior is different than _ssss_iiii_gggg_aaaa_cccc_tttt_iiii_oooo_nnnn(2)). _ssss_iiii_gggg_hhhh_oooo_llll_dddd adds _s_i_g to the calling process's signal mask. _ssss_iiii_gggg_rrrr_eeee_llll_ssss_eeee removes _s_i_g from the calling process's signal mask. _ssss_iiii_gggg_iiii_gggg_nnnn_oooo_rrrr_eeee sets the disposition for _s_i_g to _SSSS_IIII_GGGG______IIII_GGGG_NNNN. _ssss_iiii_gggg_pppp_aaaa_uuuu_ssss_eeee removes _s_i_g from the calling process's signal mask and suspends the calling process until a signal is received. This system call is useful for testing variables that are changed on the occurrence of a signal. The correct usage is to use _ssss_iiii_gggg_hhhh_oooo_llll_dddd to block the signal first, then test the variables. If they have not changed, then call _ssss_iiii_gggg_pppp_aaaa_uuuu_ssss_eeee to wait for the signal. PPPPaaaaggggeeee 1111 SSSSIIIIGGGGSSSSEEEETTTT((((2222)))) SSSSIIIIGGGGSSSSEEEETTTT((((2222)))) For a list of valid signal numbers and a general description of the signal mechanism, please see _ssss_iiii_gggg_nnnn_aaaa_llll(5). These functions will fail if one or more of the following are true: [EINVAL] _s_i_g is an illegal signal number (including _SSSS_IIII_GGGG_KKKK_IIII_LLLL_LLLL and _SSSS_IIII_GGGG_SSSS_TTTT_OOOO_PPPP) or the default handling of _s_i_g cannot be changed. [EINVAL] The requested action is illegal (e.g. ignoring _SSSS_IIII_GGGG_CCCC_OOOO_NNNN_TTTT, which is ignored by default). [EINTR] A signal was caught during the system call _ssss_iiii_gggg_pppp_aaaa_uuuu_ssss_eeee. DDDDIIIIAAAAGGGGNNNNOOOOSSSSTTTTIIIICCCCSSSS Upon successful completion, _ssss_iiii_gggg_ssss_eeee_tttt returns _SSSS_IIII_GGGG______HHHH_OOOO_LLLL_DDDD if the signal had been blocked or the signal's previous disposition if it had not been blocked. Otherwise, a value of SSSSIIIIGGGG____EEEERRRRRRRR is returned and _e_r_r_n_o is set to indicate the error. SSSSIIIIGGGG____EEEERRRRRRRR is defined in <_s_y_s/_s_i_g_n_a_l._h>. For the other functions, upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and _e_r_r_n_o is set to indicate the error. SSSSEEEEEEEE AAAALLLLSSSSOOOO csh(1), blockproc(2), kill(2), pause(2), setrlimit(2), sigaction(2), signal(2), ulimit(2), wait(2), setjmp(3C), sigvec(3B), signal(5), siginfo(5). WWWWAAAARRRRNNNNIIIINNNNGGGGSSSS Signals raised by any instruction in the instruction stream, including SSSSIIIIGGGGFFFFPPPPEEEE, SSSSIIIIGGGGIIIILLLLLLLL, SSSSIIIIGGGGEEEEMMMMTTTT, SSSSIIIIGGGGBBBBUUUUSSSS, and SSSSIIIIGGGGSSSSEEEEGGGGVVVV, will cause infinite loops if their handler returns, or the action is set to SSSSIIIIGGGG____IIIIGGGGNNNN.... This is because the exception PC at the time of the signal points to the instruction that raised the exception or signal, and resuming the process will re-execute that same instruction. The POSIX signal routines (_s_i_g_a_c_t_i_o_n(2), _s_i_g_p_e_n_d_i_n_g(2), _s_i_g_p_r_o_c_m_a_s_k(2), _s_i_g_s_u_s_p_e_n_d(2), _s_i_g_s_e_t_j_m_p(3)), and the 4.3BSD signal routines (_s_i_g_v_e_c(3B), _s_i_g_n_a_l(3B), _s_i_g_b_l_o_c_k(3B), _s_i_g_p_a_u_s_e(3B), _s_i_g_s_e_t_m_a_s_k(3B)) must NEVER be used with _s_i_g_n_a_l(2) or _s_i_g_s_e_t(2). PPPPaaaaggggeeee 2222 
