Is there a os.utime() that doesn't follow links?

[mike-ward]

I'm writing a touch program for the CoreUtils project. It appears os.utime() follows links to their source. Is there a vlib api that can set the time of symbolic links? I need it to implement the -h option of touch

[mike-ward]

I took a shot at writing a lutime function. It changes the access and mod times of the given file when I run it, but the times are wildly wrong. I'm not a C programmer so I'm stumped why this doesn't work (Mac Sonoma 14.4)

#include <sys/time.h>

fn C.lutimes(&char, voidptr) int

fn lutime(path string, actime int, modtime int) ! {
	mut u := [C.timeval{u64(actime), 0}, C.timeval{u64(modtime), 0}]
	result := C.lutimes(&char(path.str), voidptr(&u))
	if result != 0 {
		return error('lutime failed (${C.errno})')
	}
}

https://nxmnpg.lemoda.net/2/utimes

[mike-ward]

I was able to resolve the issue by using the data member of Array.

fn lutime(path string, actime int, modtime int) ! {
 	times := [C.timeval{u64(actime), u64(0)}, C.timeval{u64(modtime), u64(0)}]
	if C.lutimes(&char(path.str), voidptr(times.data)) != 0 {
		return error('lutime failed (${C.errno})')
	}
}

[JalonSolov]

The alternative would be to use a fixed array, which is only data. Since this array size is known, and will never change in size, fixed is likely better here.

 	times := [C.timeval{u64(actime), u64(0)}, C.timeval{u64(modtime), u64(0)}]!
 	if C.lutimes(&char(path.str), voidptr(&times)) != 0 {
		return error('lutime failed (${C.errno})')
	}

[mike-ward]

Fixed array generates a warning that suggests using &times[0]. (Excellent error message and diagnostic by the way)

touch.v:146:32: warning: cannot cast a fixed array (use e.g. `&arr[0]` instead)
  144 | fn lutime(path string, acctime int, modtime int) ! {
  145 |     times := [C.timeval{u64(acctime), u64(0)}, C.timeval{u64(modtime), u64(0)}]!
  146 |     if C.lutimes(&char(path.str), voidptr(times)) != 0 {
      |                                   ~~~~~~~~~~~~~~

[JalonSolov]

Ah, right. Weird the way that works, but... it does as long as you do what V wants. ;-)