error.c

哲学家就餐问题的两种算法实现

#include <errno.h>
#include <stdarg.h>
#include "ourhdr.h"

#define MAXLINE 100

static void err_doit(int, const char *, va_list);
char   *pname = 0;     /* caller can set this from argv[0] */

/* Fatal error related to a system call.
 * Print a message and terminate. */

void err_sys(const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    err_doit(1, fmt, ap);
    va_end(ap);
    exit(1);
}

/* Fatal error unrelated to a system call.
 * Print a meesage and terminate. */

void err_quit(const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    err_doit(0, fmt, ap);
    va_end(ap);
    exit(1);
}

/* Nonfatal error related to a system call.
 * Print a message and return. */

void err_ret(const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    err_doit(1, fmt, ap);
    va_end(ap);
    return;
}

/* Fatal error related to a system call.
 * Print a message, dump core, and terminate. */

void err_dump(const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    err_doit(1, fmt, ap);
    va_end(ap);
    abort();         /* dump core and terminate */
    exit(1);         /* shouldn't get here */
}

/* Nonfatal error unrelated to a system call.
 * Print a message and return. */

void err_msg(const char *fmt, ...)
{
    va_list ap;
    va_start(ap,fmt);
    err_doit(0, fmt, ap);
    va_end(ap);
    return;
}

/* Print a message and return to caller.
 * Caller specifies "errnoflag". */

static void err_doit(int errnoflag, const char *fmt, va_list ap)
{
    int errno_save;
    char buf[MAXLINE];

    errno_save = errno;
    vsprintf(buf, fmt, ap);
    if(errnoflag)
        sprintf(buf+strlen(buf), ": %s", strerror(errno_save));
    strcat(buf, "\n");
    fflush(stdout);
    fputs(buf, stderr);
    fflush(0);
    return;
}