fork1.c

来自「unix环境高级编程的源代码」· C语言 代码 · 共 30 行

#include    <sys/types.h>
#include    "ourhdr.h"

int        glob = 6;        /* external variable in initialized data */
char    buf[] = "a write to stdout\n";

int
main(void)
{
    int        var;        /* automatic variable on the stack */
    pid_t    pid;

    var = 88;
    if (write(STDOUT_FILENO, buf, sizeof(buf)-1) != sizeof(buf)-1)
        err_sys("write error");
    printf("before fork\n");    /* we don't flush stdout */

    if ( (pid = fork()) < 0)
        err_sys("fork error");
    else if (pid == 0) {        /* child */
        glob++;                    /* modify variables */
        var++;
    }
//   	else
//        sleep(2);                /* parent */

    printf("pid = %d, glob = %d, var = %d\n", getpid(), glob, var);
    exit(0);
}