utime()--Set File Access and Modification Times

 #include <utime.h>

 int utime(const char *path, const struct utimbuf *times);  

The utime() function sets the access and modification times of path to the values in the utimbuf structure. If times is a NULL pointer, the access and modification times are set to the current time. If the named file is a symbolic link, utime() resolves the symbolic link.

If the file is checked out by another user (someone other than the user profile of the current job), utime() fails with the [EBUSY] error.

When utime() completes successfully, it marks the change time of the file to be updated.

Parameters

path

(Input) A pointer to the null-terminated path name of the file for which the times should be changed.

This parameter is assumed to be represented in the CCSID (coded character set identifier) currently in effect for the job. If the CCSID of the job is 65535, this parameter is assumed to be represented in the default CCSID of the job.

See QlgUtime()--Set File Access and Modification Times (using NLS-enabled path name) for a description and an example of supplying the path in any CCSID.

times

(Input) A pointer to a structure utimbuf, which contains the times to be updated.

The structure utimbuf is defined according to the POSIX.1 definition as follows:

struct utimbuf {
   time_t   actime;   /* The new access time       */
   time_t   modtime;  /* The new modification time */
   }

The time_t type gives the number of seconds since the Epoch.

Authorities

Note: Adopted authority is not used.

Authorization Required for utime() (excluding QDLS)

Authorization Required for utime() in the QDLS File System

Return Value

0

utime() was successful. The file access and modification times are changed.

-1

utime() was not successful. The file times are not changed. The errno global variable is set to indicate the error.

Error Conditions

If utime() is not successful, errno usually indicates one of the following errors. Under some conditions, errno could indicate an error other than those listed here.

If interaction with a file server is required to access the object, errno could indicate one of the following errors:

Error Messages

The following messages may be sent from this function:

Usage Notes

1. This function will fail with error code [ENOTSAFE] when all the following conditions are true:
   • Where multiple threads exist in the job.
     
   • The object on which this function is operating resides in a file system that is not threadsafe. Only the following file systems are threadsafe for this function:
     • "Root" (/)
     • QOpenSys
     • User-defined
     • QNTC
     • QSYS.LIB
     • Independent ASP QSYS.LIB
     • QOPT
     • Network File System
     • QFileSvr.400
   
   
2. QSYS.LIB and Independent ASP QSYS.LIB File System Differences

   These file systems do not support utime().

3. QDLS File System Differences

   Changing the times of the /QDLS directory (the root folder) is not allowed.

4. QOPT File System Differences

   The QOPT file system does not support utime().

5. QNTC File System Differences

   The QNTC file system does not set the access and modification times of path. The values in the utimbuf structure are ignored.

6. When you develop in C-based languages and this function is compiled with _64_BIT_TIME defined, it will be mapped to utime_time64(). Note that the type of the times parameter, struct utimbuf *, also will be mapped to type struct utimbuf_time64 *. See utime_time64() for more information about this structure.
   
   

Related Information

• The <utime.h> file (see Header Files for UNIX^®-Type Functions)
  
• The <limits.h> file (see Header Files for UNIX-Type Functions)
  
• QlgUtime()--Set File Access and Modification Times (using NLS-enabled path name)

Example

The following example uses utime().

Note: By using the code examples, you agree to the terms of the Code license and disclaimer information.

#include <utime.h>
#include <time.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

main() {
  int file_descriptor;
  char fn[]="utime.file";
  struct utimbuf ubuf;
  struct stat info;

  if ((file_descriptor = creat(fn, S_IWUSR)) < 0)
    perror("creat() error");
  else {
    close(file_descriptor);
    puts("before utime()");
    stat(fn,&info);
    printf("  utime.file modification time is %ld\n",
           info.st_mtime);
    ubuf.modtime = 0;       /* set modification time to Epoch */
    time(&ubuf.actime);
    if (utime(fn, &ubuf) != 0)
      perror("utime() error");
    else {
      puts("after utime()");
      stat(fn,&info);
      printf("  utime.file modification time is %ld\n",
             info.st_mtime);
    }
    unlink(fn);
  }
}

Output:

before utime()
  utime.file modification time is 749323571
after utime()
  utime.file modification time is 0

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