On 23/10/20 9:23 am, Anatoli wrote:
Hi All,
Is there a way to determine with autoconf what's the base type of a typedef?
I'm trying to accomplish the following:
There are standard types time_t, off_t, size_t and similar that are defined
differently on different platforms/OS.
For example, time_t is defined as "long int" on Linux amd64, but as "long
long int" on OpenBSD amd64. So when printing a time_t var with printf & co,
on Linux it's OK to use "%ld" format specifier, but on OpenBSD it should be
"%lld".
You could use an AC_COMPILE thing to run a small bit of C that does something like:
int
test(int argc, char **argv)
{
time_t t = -1;
if(t < 0) {
if(sizeof(time_t) == sizeof(int)) {
printf("d");
}
else if(sizeof(time_t) == sizeof(long int)) {
printf("ld");
}
else if(sizeof(time_t) == sizeof(long long int)) {
printf("lld");
}
else {
printf("error");
}
}
else {
if(sizeof(time_t) == sizeof(int)) {
printf("u");
}
else if(sizeof(time_t) == sizeof(long int)) {
printf("lu");
}
else if(sizeof(time_t) == sizeof(long long int)) {
printf("llu");
}
else {
printf("error");
}
}
return 0;
}
