Output

saghul@win7dev /c/Users/saghul/src/libuv
$ gdb ./test-uptime.exe
GNU gdb (GDB) 7.4
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i686-pc-mingw32".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from c:\Users\saghul\src\libuv\test-uptime.exe...done.
(gdb) run
Starting program: c:\Users\saghul\src\libuv\test-uptime.exe
[New Thread 3552.0xf20]
[New Thread 3552.0xe14]

Program received signal SIGSEGV, Segmentation fault.
0x00401d80 in uv_uptime (uptime=0x22ff18) at src/win/util.c:432
432         if (counterDef->CounterNameTitleIndex == 674) {
(gdb) bt
#0  0x00401d80 in uv_uptime (uptime=0x22ff18) at src/win/util.c:432
#1  0x004013d1 in main (argc=1, argv=0x3c1160) at test_uptime.c:10
(gdb) f 0
#0  0x00401d80 in uv_uptime (uptime=0x22ff18) at src/win/util.c:432
432         if (counterDef->CounterNameTitleIndex == 674) {
(gdb) print counterDef
$1 = (PERF_COUNTER_DEFINITION *) 0xbaea17a5
(gdb) print counterDef->CounterNameTitleIndex
Cannot access memory at address 0xbaea17a9
(gdb)

Source test file

#include <uv.h>
#include <stdio.h>

/* Compiled lime this: gcc -Iinclude -Iinclude/uv-private -Iinclude -Iinclude/uv-private -g --std=gnu89 -D_WIN32_WINNT=0x0600 -Isrc/ares/config_win32 -D_GNU_SOURCE  -o test-uptime test_uptime.c uv.a -lws2_32 -lpsapi -liphlpapi -lm
*/

int main(int argc, char **argv)
{
	double uptime;
	uv_err_t err;
	
	err = uv_uptime(&uptime);
	if (err.code == UV_OK) {
		printf("-- UPTIME: %f\n", uptime);
	} else {
		printf("-- UPTIME ERROR: %d\n", err.code);
	}

	return 0;
}