bsd_signal(3c)

1bsd_signal(3C)           Standard C Library Functions           bsd_signal(3C)
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NAME

6       bsd_signal - simplified signal facilities
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SYNOPSIS

9       #include <signal.h>
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11       void (*bsd_signal(int sig, void (*func)(int)))(int);
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DESCRIPTION

15       The bsd_signal() function provides a partially compatible interface for
16       programs written to historical system interfaces (see USAGE below).
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19       The function call bsd_signal(sig, func) has an effect as if implemented
20       as:
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22         void (*bsd_signal(int sig, void (*func)(int)))(int)
23         {
24              struct sigaction act, oact;
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26              act.sa_handler = func;
27              act.sa_flags = SA_RESTART;
28              sigemptyset(&act.sa_mask);
29              sigaddset(&act.sa_mask, sig);
30              if (sigaction(sig, &act, &oact) == −1)
31                   return(SIG_ERR);
32              return(oact.sa_handler);
33         }
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37       The handler function should be declared:
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39         void handler(int sig);
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43       where sig is the signal number.  The behavior is undefined if func is a
44       function that takes more than one argument, or an argument of a differ‐
45       ent type.
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RETURN VALUES

48       Upon  successful  completion,  bsd_signal() returns the previous action
49       for sig. Otherwise, SIG_ERR is returned and errno is  set  to  indicate
50       the error.
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ERRORS

53       Refer to sigaction(2).
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USAGE

56       This function is a direct replacement for the BSD signal(3UCB) function
57       for simple applications that are installing  a  single-argument  signal
58       handler  function.  If a BSD signal handler function is being installed
59       that expects more than one argument, the application has to be modified
60       to  use  sigaction(2).  The  bsd_signal()  function  differs  from sig‐
61       nal(3UCB) in that the SA_RESTART flag is set and the SA_RESETHAND  will
62       be  clear  when  bsd_signal() is used.  The state of these flags is not
63       specified for signal(3UCB).
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ATTRIBUTES

66       See attributes(5) for descriptions of the following attributes:
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71       ┌─────────────────────────────┬─────────────────────────────┐
72       │ATTRIBUTE TYPE               │ATTRIBUTE VALUE              │
73       ├─────────────────────────────┼─────────────────────────────┤
74       │Interface Stability          │Standard                     │
75       └─────────────────────────────┴─────────────────────────────┘
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