Linux信号处理函数sigprocmask()使用方法讲解

一时失言乱红尘 2021-12-16 08:21 486阅读 0赞

我们看一下sigprocmask()函数的使用方法.

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjA0ODQ2Mw_size_16_color_FFFFFF_t_70][]

![20190705155404342.png][]

下面我们再写一个简单的例子来熟悉sigprocmask()函数及其配套使用函数.

SIG\_UNBLOCK参数的使用:

\#include <signal.h>

\#include <stdio.h>

\#include <stdlib.h>

int main()

int i;

sigset\_t newmask, oldmask;

i = 1;

while(i <= 3)

sleep(1);

i += 1;

sigemptyset(&newmask);

sigaddset(&newmask, SIGINT);

if (sigprocmask(SIG\_BLOCK, &newmask, &oldmask) < 0)

fprintf(stderr, "SIG\_BLOCK error\\n");

exit(1);

else

printf("SIGINT blocked.\\n");

i = 1;

while(i <= 5)

sleep(1);

i += 1;

printf("--------------------------------------\\n");

if(sigprocmask(SIG\_UNBLOCK, &newmask, NULL) < 0)

fprintf(stderr, "SIG\_UNBLOCK error\\n");

else

printf("SIGINT unblocked.\\n");

while(1);

在3s内按下组合键Ctrl + C.

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjA0ODQ2Mw_size_16_color_FFFFFF_t_70 1][]

在3s~8s中按下组合键Ctrl + C.

在这种情况下，我们看到了阻塞信号和屏蔽信号的区别.

这里在SIGINT信号阻塞后再向进程发送该信号，该信号会阻塞，直到下面第一个参数为UNBLOCK的sigprocmask()函数成功执行，这时刚才的SIGINT信号会立即传送到该进程：所以，SIGINT Unblocked未输出，进程就结束了.

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjA0ODQ2Mw_size_16_color_FFFFFF_t_70 2][]

在8s后按下组合键Ctrl + C.

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjA0ODQ2Mw_size_16_color_FFFFFF_t_70 3][]

SIG\_SETMASK参数的使用:

\#include <signal.h>

\#include <stdio.h>

\#include <stdlib.h>

int main()

int i;

sigset\_t newmask1, newmask2, oldmask;

i = 1;

while(i <= 3)

sleep(1);

i += 1;

sigemptyset(&newmask1);

sigemptyset(&newmask2);

sigaddset(&newmask1, SIGINT);

sigaddset(&newmask2, SIGQUIT);

if (sigprocmask(SIG\_BLOCK, &newmask1, &oldmask) < 0)

fprintf(stderr, "SIG\_BLOCK error\\n");

exit(1);

else

printf("SIGINT blocked.\\n");

i = 1;

while(i <= 5)

sleep(1);

i += 1;

printf("--------------------------------------\\n");

if(sigprocmask(SIG\_SETMASK, &newmask2, NULL) < 0)

fprintf(stderr, "SIG\_SETMASK error\\n");

else

printf("SIGINT unblocked and SIGQUIT blocked.\\n");

while(1);

8s后，SIGINT信号由阻塞状态变为正常，SIGQUIT信号由正常变为阻塞状态.

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjA0ODQ2Mw_size_16_color_FFFFFF_t_70 2][]

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[20190705155404342.png]: /images/20211214/7bfefd2cb93946d78fb60acfcced1765.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjA0ODQ2Mw_size_16_color_FFFFFF_t_70 1]: /images/20211214/80c78b180c624ca1914ce6b5e1bcd27b.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjA0ODQ2Mw_size_16_color_FFFFFF_t_70 2]: /images/20211214/64858ab5f1db492c8d4cd1bba8c9350d.png
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