time-util: fix build with gcc8 -Werror=format-truncation=

* it fails with gcc8 when -O1 or -Os is used (and -ftree-vrp which is added by -O2 and higher isn't used)

../git/src/basic/time-util.c: In function 'format_timespan':
../git/src/basic/time-util.c:508:46: error: '%0*llu' directive output between 1 and 2147483647 bytes may cause result to exceed 'INT_MAX' [-Werror=format-truncation=]
                                              "%s"USEC_FMT".%0*"PRI_USEC"%s",
                                              ^~~~
../git/src/basic/time-util.c:508:60: note: format string is defined here
                                              "%s"USEC_FMT".%0*"PRI_USEC"%s",
../git/src/basic/time-util.c:508:46: note: directive argument in the range [0, 18446744073709551614]
                                              "%s"USEC_FMT".%0*"PRI_USEC"%s",
                                              ^~~~
../git/src/basic/time-util.c:507:37: note: 'snprintf' output 4 or more bytes (assuming 2147483651) into a destination of size 4294967295
                                 k = snprintf(p, l,
                                     ^~~~~~~~~~~~~~
                                              "%s"USEC_FMT".%0*"PRI_USEC"%s",
                                              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                              p > buf ? " " : "",
                                              ~~~~~~~~~~~~~~~~~~~
                                              a,
                                              ~~
                                              j,
                                              ~~
                                              b,
                                              ~~
                                              table[i].suffix);
                                              ~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors

[zj: change 'char' to 'signed char']

diff --git a/src/basic/time-util.c b/src/basic/time-util.c
index 73484473189dc6e558b141e776c6b92e3fadff25..dc8db13c261a5327451ec4f27833ffd5a449c8e6 100644 (file)
--- a/src/basic/time-util.c
+++ b/src/basic/time-util.c
@@ -494,7 +494,7 @@ char *format_timespan(char *buf, size_t l, usec_t t, usec_t accuracy) {
                 /* Let's see if we should shows this in dot notation */
                 if (t < USEC_PER_MINUTE && b > 0) {
                         usec_t cc;
-                        int j;
+                        signed char j;
 
                         j = 0;
                         for (cc = table[i].usec; cc > 1; cc /= 10)