如何确定Linux系统调用号及其用途？

系统调用名称	系统调用号
restart_syscall	0
exit	1
fork	2
read	3
write	4
open	5
close	6
waitpid	7
creat	8
link	9
unlink	10
execve	11
chdir	12
time	13
mknod	14
chmod	15
lchown	16
break	17
oldstat	18
lseek	19
getpid	20
mount	21
umount	22
setuid	23
getuid	24
stime	25
ptrace	26
alarm	27
oldfstat	28
pause	29
utime	30
stty	31
gtty	32
access	33
nice	34
ftime	35
sync	36
kill	37
rename	38
mkdir	39
rmdir	40
dup	41
pipe	42
times	43
prof	44
brk	45
setgid	46
getgid	47
signal	48
geteuid	49
getegid	50
acct	51
umount2	52
lock	53
ioctl	54
fcntl	55
mpx	56
setpgid	57
ulimit	58
oldolduname	59
umask	60
chroot	61
ustat	62
dup2	63
getppid	64
getpgrp	65
setsid	66
sigaction	67
sgetmask	68
ssetmask	69
setreuid	70
setregid	71
sigsuspend	72
sigpending	73
sethostname	74
setrlimit	75
getrlimit	76
getrusage	77
gettimeofday	78
settimeofday	79
getgroups	80
setgroups	81
select	82
symlink	83
oldlstat	84
readlink	85
uselib	86
swapon	87
reboot	88
readdir	89
mmap	90
munmap	91
truncate	92
ftruncate	93
fchmod	94
fchown	95
getpriority	96