Linux System Programming note 10 —— Signal

1. SIGKILL和SIGSTOP不能被忽略

2. Signal Identifiers

<signal.h>

3. Basic Signal Management

#include <signal.h>

typedef void (*sighandler_t)(int);

sighandler_t signal(int signo, sighandler_t handler);

4. Waiting for a Signal, Any Signal

#include <unistd.h>

int pause(void);

5. Mapping Signal Numbers to Strings

extern const char * const sys_siglist[];

#include <signal.h>

void psignal(int signo, const char *msg);

 

#define _GNU_SOURCE

#include  *strsignal(int signo);

6. Sending a Signal

#include <sys/types.h>

#include <signal.h>

int kill(pid_t pid, int signo);

7. Sending a Signal to Yourself

#include <signal.h>

int raise(int signo);

example:

raise(signo) equals to kill(getpid(), signo);

8. Sending a Signal to an Entire Process Group

#include <signal.h>

int killpg(int pgrp, int signo);

example:

killpg(pgrp, signo) equals to kill(-pgrp, signo);

9. Guaranteed-Reentrant Functions

10. Signal Sets

#include <signal.h>

int sigemptyset(sigset_t *set);

int sigfillset(sigset_t *set);

int sigaddset(sigset_t *set, int signo);

int sigdelset(sigset_t *set, int signo);

int sigismember(const sigset_t *set, int signo);

10. More Signal Set Functions

#define  _GNU_SOURCE

#define <signal.h>

int sigisemptyset(sigset_t *set);

int sigorset(sig_set *dest, sigset_t *left, sigset_t *right);

int sigandset(sig_set *dest, sigset_t *left, sigset_t *right);

11. Blocking Signals

#include <signal.h>

int sigprocmask(int how, const sigset_t *set, sigset_t *oldset);

how:

SIG_SETMASK

SIG_BLOCK

SIG_UNBLOCK

12. Retrieving Pending Signals

#include <signal.h>

int sigpending(sigset_t *set);

13. Waiting for a Set of Signals

#include <signal.h>

int sigsuspend(const sigset_t *set);

14. Advanced Signal Management

#include <signal.h>

int sigaction(int signo, const struct sigaction *act,

                  struct sigaction *oldact);

struct sigaction{

     void (*sa_handler)(int);

     void (*sa_sigaction)(int, siginfo_t *, void *);

     sigset_t sa_mask;

     int sa_flags;

     void (*sa_restorer)(void);

};

typedef struct siginfo_t {

     int si_signo;

     int si_errno;

     int si_code;

     pid_t si_pid;

     uid_t si_uid;

     int si_status;

     clock_t si_utime;

     clock_t si_stime;

     sigval_t si_value;

     int si_int;

     void *si_ptr;

     void *si_addr;

     int si_band;

     int si_fd;

};

15. Sending a Signal with a Payload

#include <signal.h>

int sigqueue(pid_t pid,

                  int signo,

                  const union sigval value);

union sigval{

     int sival_int;

     void *sival_ptr;

};