Allow the res argument to clock_getres() to be NULL.

diff --git a/libc/sysdeps/linux/common/clock_getres.c b/libc/sysdeps/linux/common/clock_getres.c
index 8ee7828..93487c3 100644 (file)
--- a/libc/sysdeps/linux/common/clock_getres.c
+++ b/libc/sysdeps/linux/common/clock_getres.c
@@ -18,15 +18,18 @@ libc_hidden_proto(sysconf)
 
 int clock_getres(clockid_t clock_id, struct timespec* res)
 {
-       long clk_tck;
        int retval = -1;
 
        switch (clock_id) {
                case CLOCK_REALTIME:
-                       if ((clk_tck = sysconf(_SC_CLK_TCK)) < 0)
-                               clk_tck = 100;
-                       res->tv_sec = 0;
-                       res->tv_nsec = 1000000000 / clk_tck;
+                       if (res) {
+                               long clk_tck;
+
+                               if ((clk_tck = sysconf(_SC_CLK_TCK)) < 0)
+                                       clk_tck = 100;
+                               res->tv_sec = 0;
+                               res->tv_nsec = 1000000000 / clk_tck;
+                       }
                        retval = 0;
                        break;