Preview Ruby 4.1 is a preview. It can change before the final release. Switch to Ruby 4.0 →
instance method
IO#close_on_exec=
(::boolish bool) -> nil
self.close_on_exec = bool → true or false
io.c
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static VALUE
rb_io_set_close_on_exec(VALUE io, VALUE arg)
{
int flag = RTEST(arg) ? FD_CLOEXEC : 0;
rb_io_t *fptr;
VALUE write_io;
int fd, ret;
write_io = GetWriteIO(io);
if (io != write_io) {
GetOpenFile(write_io, fptr);
if (fptr && 0 <= (fd = fptr->fd)) {
if ((ret = fcntl(fptr->fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
if ((ret & FD_CLOEXEC) != flag) {
ret = (ret & ~FD_CLOEXEC) | flag;
ret = fcntl(fd, F_SETFD, ret);
if (ret != 0) rb_sys_fail_path(fptr->pathv);
}
}
}
GetOpenFile(io, fptr);
if (fptr && 0 <= (fd = fptr->fd)) {
if ((ret = fcntl(fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
if ((ret & FD_CLOEXEC) != flag) {
ret = (ret & ~FD_CLOEXEC) | flag;
ret = fcntl(fd, F_SETFD, ret);
if (ret != 0) rb_sys_fail_path(fptr->pathv);
}
}
return Qnil;
}
Sets a close-on-exec flag.
Example
f = File.open(File::NULL) f.close_on_exec = true system("cat", "/proc/self/fd/#{f.fileno}") # cat: /proc/self/fd/3: No such file or directory f.closed? #=> false
Ruby sets close-on-exec flags of all file descriptors by default since Ruby 2.0.0. So you don’t need to set by yourself. Also, unsetting a close-on-exec flag can cause file descriptor leak if another thread use fork() and exec() (via system() method for example). If you really needs file descriptor inheritance to child process, use spawn()‘s argument such as fd=>fd.