/* This file comes from APUE, slightly edited by NetXRay@byhh */#include "myerr.h"static void	err_doit(int, const char *, va_list);/* Nonfatal error related to a system call. * Print a message and return. */voiderr_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 and terminate. */voiderr_sys(const char *fmt, ...){    va_list		ap;    va_start(ap, fmt);    err_doit(1, fmt, ap);    va_end(ap);    exit(1);}/* Fatal error related to a system call. * Print a message, dump core, and terminate. */voiderr_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. */voiderr_msg(const char *fmt, ...){    va_list		ap;    va_start(ap, fmt);    err_doit(0, fmt, ap);    va_end(ap);    return;}/* Fatal error unrelated to a system call. * Print a message and terminate. */voiderr_quit(const char *fmt, ...){    va_list		ap;    va_start(ap, fmt);    err_doit(0, fmt, ap);    va_end(ap);    exit(1);}/* Print a message and return to caller. * Caller specifies "errnoflag". */static voiderr_doit(int errnoflag, const char *fmt, va_list ap){    int		errno_save;    char	buf[4096];    errno_save = errno;		/* value caller might want printed */    vsprintf(buf, fmt, ap);    if (errnoflag)        sprintf(buf+strlen(buf), ": %s", strerror(errno_save));    strcat(buf, "\n");    fflush(stdout);		/* in case stdout and stderr are the same */    fputs(buf, stderr);    fflush(NULL);		/* flushes all stdio output streams */    return;}