wait.h

一个简单的操作系统minix的核心代码

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				include/sys/wait.h	 	 
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02500	/* The <sys/wait.h> header contains macros related to wait(). The value
02501	 * returned by wait() and waitpid() depends on whether the process 
02502	 * terminated by an exit() call, was killed by a signal, or was stopped
02503	 * due to job control, as follows:
02504	 *
02505	 *                               High byte   Low byte
02506	 *                              +---------------------+
02507	 *      exit(status)            |  status  |    0     |
02508	 *                              +---------------------+
02509	 *      killed by signal        |    0     |  signal  |
02510	 *                              +---------------------+
02511	 *      stopped (job control)   |  signal  |   0177   |
02512	 *                              +---------------------+
02513	 */
02514	
02515	#ifndef _WAIT_H
02516	#define _WAIT_H
02517	
02518	#define _LOW(v)         ( (v) & 0377)
02519	#define _HIGH(v)        ( ((v) >> 8) & 0377)
02520	
02521	#define WNOHANG         1       /* do not wait for child to exit */
02522	#define WUNTRACED       2       /* for job control; not implemented */
02523	
02524	#define WIFEXITED(s)    (_LOW(s) == 0)                      /* normal exit */
02525	#define WEXITSTATUS(s)  (_HIGH(s))                          /* exit status */
02526	#define WTERMSIG(s)     (_LOW(s) & 0177)                    /* sig value */
02527	#define WIFSIGNALED(s)  (((unsigned int)(s)-1 & 0xFFFF) < 0xFF) /* signaled */
02528	#define WIFSTOPPED(s)   (_LOW(s) == 0177)                   /* stopped */
02529	#define WSTOPSIG(s)     (_HIGH(s) & 0377)                   /* stop signal */
02530	
02531	/* Function Prototypes. */
02532	#ifndef _ANSI_H
02533	#include <ansi.h>
02534	#endif
02535	
02536	_PROTOTYPE( pid_t wait, (int *_stat_loc)                                   );
02537	_PROTOTYPE( pid_t waitpid, (pid_t _pid, int *_stat_loc, int _options)      );
02538	
02539	#endif /* _WAIT_H */