美人心计雪鸢死第几集:C++高手来！！！！！！！！

下面的函数定义的代码是什么意思？？谁能帮小弟我分析下，我很多地方看不懂``````谢谢！！！

int
XRE_main(int argc, char* argv[], const nsXREAppData* aAppData)
{
nsresult rv;
NS_TIMELINE_MARK("enter main");

#ifdef DEBUG
if (PR_GetEnv("XRE_MAIN_BREAK"))
NS_BREAK();
#endif

#ifdef XP_WIN32
// Suppress the "DLL Foo could not be found" dialog, such that if dependent
// libraries (such as GDI+) are not preset, we gracefully fail to load those
// XPCOM components, instead of being ungraceful.
SetErrorMode(SEM_FAILCRITICALERRORS);

#ifdef DEBUG
// Disable small heap allocator to get heapwalk() giving us
// accurate heap numbers. Win2k non-debug does not use small heap allocator.
// Win2k debug seems to be still using it.
// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vclib/html/_crt__set_sbh_threshold.asp
_set_sbh_threshold(0);
#endif
#endif

#if defined(XP_UNIX) || defined(XP_BEOS)
InstallUnixSignalHandlers(argv[0]);
#endif

// Unbuffer stdout, needed for tinderbox tests.
setbuf(stdout, 0);

#if defined(FREEBSD)
// Disable all SIGFPE's on FreeBSD, as it has non-IEEE-conformant fp
// trap behavior that trips up on floating-point tests performed by
// the JS engine. See bugzilla bug 9967 details.
fpsetmask(0);
#endif

gArgc = argc;
gArgv = argv;

NS_ASSERTION(aAppData, "must specify XUL app data");

// In the future when nsXREAppData is extended, this check will need to
// have more finesse.
if (aAppData->size < sizeof(nsXREAppData)) {
NS_ERROR("aAppdata.size isn't set properly!");
return 1;
}