/* sigactdemo.c
 *               purpose: shows use of sigaction()
 *               feature: blocks ^\ while handling ^C
 *                        does not reset ^C handler, so two kill
 */

#include    <stdio.h>
#include    <signal.h>
#define    INPUTLEN    100

main()
{
    struct sigaction newhandler;            /* new settings        */
    sigset_t         blocked;               /* set of blocked sigs */
    void         inthandler();          /* the handler         */
    char         x[INPUTLEN];

    /* load these two members first */
    newhandler.sa_handler = inthandler;      /* handler function    */
    newhandler.sa_flags = SA_RESETHAND | SA_RESTART;  /* options    */

    /* then build the list of blocked signals */
    sigemptyset(&blocked);                  /* clear all bits      */
    sigaddset(&blocked, SIGQUIT);        /* add SIGQUIT to list */

    newhandler.sa_mask = blocked;        /* store blockmask     */

    if ( sigaction(SIGINT, &newhandler, NULL) == -1 )
        perror("sigaction");
    else
        while( 1 ){
            fgets(x, INPUTLEN, stdin);
            printf("input: %s", x);
        }
}

void inthandler(int s)
{
    printf("Called with signal %d\n", s);
    sleep(s);
    printf("done handling signal %d\n", s);
}

Unix/Linux系統(tǒng)編程實(shí)踐教程一書P205頁例子，上面使用函數(shù)sigaction，主要是演示在處理SIGINT(ctrl + C)時(shí)阻塞SIGQUIT(ctrl + ),搜了下結(jié)構(gòu)體sigcation中sa_mask的作用是要阻塞的信號當(dāng)在處理時(shí)，因此用sigaddset等函數(shù)添加了SIGQUIT信號，可是執(zhí)行時(shí)卻報(bào)錯(cuò)

[root@centos-linux-7 CH07]# ./sigactdemo 
^\退出(吐核)
[root@centos-linux-7 CH07]# gcc -v
使用內(nèi)建 specs。
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/4.8.5/lto-wrapper
目標(biāo)：x86_64-redhat-linux
配置為：../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-linker-hash-style=gnu --enable-languages=c,c++,objc,obj-c++,java,fortran,ada,go,lto --enable-plugin --enable-initfini-array --disable-libgcj --with-isl=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/isl-install --with-cloog=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/cloog-install --enable-gnu-indirect-function --with-tune=generic --with-arch_32=x86-64 --build=x86_64-redhat-linux
線程模型：posix
gcc 版本 4.8.5 20150623 (Red Hat 4.8.5-28) (GCC) 
[root@centos-linux-7 CH07]#