一、sleep函数#include <unistd.h>unsigned int sleep(unsigned int seconds);参数：休眠秒数返回值：返回0或未休眠的秒数（见下面介绍）功能：sleep函数使进程被挂起，直到满足下面两个条件之一才返回①已经过了参数seconds所指定的时间。......
time函数定义 #include <time.h> time_t time(time_t *t);功能描述time() returns the time since the Epoch (00:00:00 UTC, January 1, 1970), measured in seconds.If t is non-NULL, the return value is also stored in the memory pointed to by t.返回值On.....
shadow文件存放在/etc/shadowstruct spwd {char sp_namp; / user login name */char sp_pwdp; / encrypted password /long int sp_lstchg; / last password change /long int sp_min; / days until change allowed. /long int sp_max; .._crypt和shadow的api...
