Linux下confstr与uname函数_获取C库与内核信息

Linux下confstr与uname函数_获取C库与内核信息

#include <stdio.h>
#include <sys/utsname.h> //uname

int main(int argc, char **argv[])
{
 struct utsname  u;
 if (uname(&u) != -1) {
  printf("获取当前内核的名称和信息如下\n"
      "sysname:%s\n"
      "nodename:%s\n"
      "release:%s\n"
      "version:%s\n"
      "machine:%s\n"
      , u.sysname, u.nodename, u.release, u.version, u.machine);
 }

 return 0;
}

输出如下:‘

获取当前内核的名称和信息如下
sysname:Linux
nodename:fes
release:2.6.32-220.el6.x86_64
version:#1 SMP Wed Nov 9 08:03:13 EST 2011
machine:x86_64

size_t confstr(int name, char *buf, size_t len);
confstr函数获取依赖配置的字符串变量的值
1、_CS_GNU_LIBC_VERSION，the GNU C library version on this system
2、_CS_GNU_LIBPTHREAD_VERSION，the POSIX implementation supplied by this C library
3、_CS_PATH,A value for the PATH variable which indicates where all the POSIX.2 standard utilities can be found.

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>  //confstr

int main(int argc, char **argv[])
{
 char *pathbuf, *gun_libpthread_version_buf, *gun_libc_version_buf;
 size_t n;

 n = confstr(_CS_PATH,NULL,(size_t) 0);
 pathbuf = malloc(n);
 if (pathbuf == NULL)
  abort();
 confstr(_CS_PATH, pathbuf, n);
 printf("_CS_PATH, A value for the PATH variable:%s\n", pathbuf);
 free(pathbuf);
 pathbuf = NULL;

 n = confstr(_CS_GNU_LIBPTHREAD_VERSION,NULL,(size_t) 0);
 if (n > 0) {
  gun_libpthread_version_buf = malloc(n);
 }
 if (gun_libpthread_version_buf == NULL)
  abort();
 confstr(_CS_GNU_LIBPTHREAD_VERSION, gun_libpthread_version_buf, n);
 printf("_CS_GNU_LIBPTHREAD_VERSION, the POSIX implementation supplied by this C library:%s\n", gun_libpthread_version_buf);
 free(gun_libpthread_version_buf);
 gun_libpthread_version_buf = NULL;

 n = confstr(_CS_GNU_LIBC_VERSION,NULL,(size_t) 0);
 if (n > 0) {
  gun_libc_version_buf = malloc(n);
 }
 if (gun_libc_version_buf == NULL)
  abort();
 confstr(_CS_GNU_LIBC_VERSION, gun_libc_version_buf, n);
 printf("_CS_GNU_LIBC_VERSION, the GNU C library version on this system: %s\n" \
   , gun_libc_version_buf);
 free(gun_libc_version_buf);
 gun_libc_version_buf = NULL;

 return 0;
}

输出结果如下:

_CS_PATH, A value for the PATH variable:/bin:/usr/bin
_CS_GNU_LIBPTHREAD_VERSION, the POSIX implementation supplied by this C library:NPTL 2.12
_CS_GNU_LIBC_VERSION, the GNU C library version on this system: glibc 2.12