I ran into trouble when I built Postgres using musl on a modern Linux and tried to run it on an old Linux. The problem seemed to involve gettimeofday() so I tried this sample program.
$ cat test_time.c
#include <sys/time.h>
#include <stdio.h>
#include <errno.h>
int main(int argc, char *argv[])
{
struct timeval now;
int rc;
rc=gettimeofday(&now, NULL);
if(rc==0) {
printf("gettimeofday() successful.\n");
printf("time = %u.%06u\n",
now.tv_sec, now.tv_usec);
}
else {
printf("gettimeofday() failed, errno = %d\n",
errno);
return -1;
}
return 0;
}
$
I compiled the following and ran it on Ubuntu 13.10. Looks good.
$ test_time
gettimeofday() successful.
time = 1397440671.749296
$ strace test_time
execve("/home/mudd/musl/test_time", ["test_time"], [/* 32 vars */]) = 0
clock_gettime(CLOCK_REALTIME, {1397440676, 660111683}) = 0
ioctl(1, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
writev(1, [{"gettimeofday() successful.", 26}, {"\n", 1}], 2gettimeofday() successful.
) = 27
writev(1, [{"time = 1397440676.660111", 24}, {"\n", 1}], 2time = 1397440676.660111
) = 25
exit_group(0) = ?
$
Then I moved the executable to my old Linux and got this. Similar to what happened with Postgres.
$ test_time
gettimeofday() successful.
time = 300.000000
$ strace test_time
execve("/home/jmudd/musl/test_time", ["test_time"], [/* 27 vars */]) = 0
clock_gettime(0, 0xbfffae48) = -1 ENOSYS (Function not implemented)
gettimeofday(NULL, {300, 0}) = 0
ioctl(1, TCGETS, {B38400 opost isig icanon echo ...}) = 0
writev(1, [{"gettimeofday() successful.", 26}, {"\n", 1}], 2gettimeofday() successful.
) = 27
writev(1, [{"time = 300.000000", 17}, {"\n", 1}], 2time = 300.000000
) = 18
exit_group(0) = ?
$