glibc

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vi /etc/nsswitch.conf hosts: files dns networks: files 改成: hosts: files dns wins networks: files 最近碰到了这么一个问题: ping一个域名domain_name的时候提示”ping: unknown host domain_name“，但是ping域名对应的IP地址 (使用host或nslookup获取) 却没有问题。 libc && glibc 　　标准C库 (the standard C library) 实现了ISO C标准，包含了一套所有C程序都可以使用的函数。libc通常被用作the standard C library的简写。 　　libc也被用作一个标准C库的实现的名字。在19世纪90年代早期，Linux内核的开发者把glibc 1.x独立了出来 (forked glibc)，并把它称为”Linux libc”，也简称为libc。Linux libc主要发布了2, 3, 4, 5四个版本。 　　1997年，FSF发布了glibc 2.0，它对POSIX标准有更好的支持，并且代码的可移植性更好。因此，现在所有主要的Linux发行版都是使用glibc。 　　Linux libc的最后的so-name是libc.so.5。因此后来的glibc 2.x使用的so

I want to intercept all file system access that occurs inside of dlopen(). At first, it would seem like LD_PRELOAD or -Wl,-wrap, would be viable solutions, but I have had trouble making them work due to some technical reasons: ld.so has already mapped its own symbols by the time LD_PRELOAD is processed. It's not critical for me to intercept the initial loading, but the _dl_* worker functions are resolved at this time, so future calls go through them. I think LD_PRELOAD is too late. Somehow malloc circumvents the issue above because the malloc() inside of ld.so does not have a functional free()

I'm experiencing a bizarre issue where my system clock knows that it's daylight savings time, but glibc seems not to. This is an up-to-date Ubuntu installation, and I have checked /etc/localtime and it has the correct changeover time for last week's switch to DST. The current correct timezone for me is Pacific Daylight Time (UTC-7). When I ask my system what time zone I'm in, it tells me correctly: $ date +%z -0700 But when I run the following program: #include <time.h> #include <stdio.h> int main() { tzset(); printf("%lu\n", timezone); return 0; } The output is, incorrectly: 28800 Which

If our server (running on a device) starts before a DHCP lease had been acquired then it can never connect using a hostname. If that happens it can find hosts by IP address but not by DNS. I initially thought that the Curl DNS cache was at fault as the curl connections failed. But I used CURLOPT_DNS_CACHE_TIMEOUT to prevent curl from caching address but connections still failed. It turns out that glibc gethostbyname_r won't automatically reload it's configuration if that configuration changes. You have to manually call res_init. See bug report below. Note: Neither the man page for

The modern glibc binary is called libc.so.6 in Linux. Why is "6" used here? The libc.so.1 or libc.so.8 can be good names too IMHO. Wikipedia gives some history at http://en.wikipedia.org/wiki/GNU_C_Library but doesn't explain fully In the early 1990s, the developers of the Linux kernel forked glibc. Their fork, called "Linux libc", was maintained separately for years and released versions 2 through 5. When FSF released glibc 2.0 in January 1997, .... At this point, the Linux kernel developers discontinued their fork and returned to using FSF's glibc.[6] The last used version of Linux libc used

I have a system that I do not have root access to, but I need to install the current version of GCC (4.7.2) on. The system is running an x86_64 build of Linux 2.6.18 and already has GCC 4.1 (without C++ support even though --version says it was built with it). EDIT 5: At this point, the steps below are just one set of things that I've tried. I've started clean a few times since then. I'm looking for someone to detail the exact order I need to make everything in with all of the switches required. This is the process I've gone through so far (where ROOT is a folder in my home directory) make-3