File time (Unix environment advanced programming)

Each file maintains three time fields for the purpose shown in the following table:

Field

Description

Example

Ls (1) option

St_atime

Last-access time of file data

Read

-u

St_mtime

Last-modification time of file data

Write

Default

St_ctime

Last-change time of i-node status

Chmod, chown

-c

Sample code on page 118:

$cat 4: 21.C # include # include int main (int argc, char * argv []) {int I, fd; struct stat statbuf; struct utimbuf timebuf; for (I = 1; I < argc; iTunes +) {if (stat (argv [I], & statbuf) < 0) {printf ("% s: stat error", argv [I]); continue } if ((fd = open (argv [I], O_RDWR | O_TRUNC) < 0) {printf ("% s: open error", argv [I]); continue;} close (fd); timebuf.actime = statbuf.st_atime; timebuf.modtime = statbuf.st_mtime; if (utime (argv [I], & timebuf) < 0) {printf ("% s: utime error", argv [I]) Continue;}} exit (0);}

The running result is:

$gcc-g-o 4 modified 21 4_21.c# View Last modified time $ls-l foo bar-rw- 1 richard richard 0 Dec 4 2014 bar-rw- 1 richard richard 0 Dec 4 2014 foo# View Last visit time $ls-lu foo bar-rw- 1 richard richard 0 Mar 20 20:41 bar-rw- 1 richard richard 0 Mar 20 20:41 foo# prints current time $dateSat Aug 29 13:13:26 CST 2011Executor $. / 4 hours 21 foo bar# check results $ls-l foo bar-rw- 1 richard richard 0 Dec 4 2014 bar-rw- 1 richard richard 0 Dec 4 2014 foo# check Last access time $ls-lu foo bar-rw- 1 richard richard 0 Mar 20 20:41 bar-rw -1 richard richard 0 Mar 20 20:41 foo# check Last State change time $ls-lc foo bar-rw- 1 richard richard 0 Aug 29 13:13 bar-rw- 1 richard richard 0 Aug 29 13:13 foo