diff options
Diffstat (limited to 'tests/usleep.c')
-rw-r--r-- | tests/usleep.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/tests/usleep.c b/tests/usleep.c new file mode 100644 index 0000000..c7e1154 --- /dev/null +++ b/tests/usleep.c @@ -0,0 +1,58 @@ +/* Pausing execution of the current thread. + Copyright (C) 2009-2017 Free Software Foundation, Inc. + Written by Eric Blake <ebb9@byu.net>, 2009. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* This file is _intentionally_ light-weight. Rather than using + select or nanosleep, both of which drag in external libraries on + some platforms, this merely rounds up to the nearest second if + usleep() does not exist. If sub-second resolution is important, + then use a more powerful interface to begin with. */ + +#include <config.h> + +/* Specification. */ +#include <unistd.h> + +#include <errno.h> + +#ifndef HAVE_USLEEP +# define HAVE_USLEEP 0 +#endif + +/* Sleep for MICRO microseconds, which can be greater than 1 second. + Return -1 and set errno to EINVAL on range error (about 4295 + seconds), or 0 on success. Interaction with SIGALARM is + unspecified. */ + +int +usleep (useconds_t micro) +{ + unsigned int seconds = micro / 1000000; + if (sizeof seconds < sizeof micro && micro / 1000000 != seconds) + { + errno = EINVAL; + return -1; + } + if (!HAVE_USLEEP && micro % 1000000) + seconds++; + while ((seconds = sleep (seconds)) != 0); + +#undef usleep +#if !HAVE_USLEEP +# define usleep(x) 0 +#endif + return usleep (micro % 1000000); +} |