You didn't include a full, compilable test case. So I built one. This works for me on CentOS 6 x64. I'm also running this as a normal user account.
Source
#include <cassert>
#include <cstdio>
#include <libusb-1.0/libusb.h>
int main() {
libusb_context *context = NULL;
libusb_device **list = NULL;
int rc = 0;
ssize_t count = 0;
rc = libusb_init(&context);
assert(rc == 0);
count = libusb_get_device_list(context, &list);
assert(count > 0);
for (size_t idx = 0; idx < count; ++idx) {
libusb_device *device = list[idx];
libusb_device_descriptor desc = {0};
rc = libusb_get_device_descriptor(device, &desc);
assert(rc == 0);
printf("Vendor:Device = %04x:%04x\n", desc.idVendor, desc.idProduct);
}
libusb_free_device_list(list, count);
libusb_exit(context);
}
Output
Vendor:Device = 1d6b:0002
Vendor:Device = 1d6b:0002
Vendor:Device = 8087:0020
Vendor:Device = 8087:0020
Vendor:Device = 0424:2514
Vendor:Device = 10c4:ea60
Vendor:Device = 051d:0002
Vendor:Device = 0624:0248