应用层获取内核版本号

1. man 2 uname

$ man 2 uname

UNAME(2)                               Linux Programmer's Manual                              UNAME(2)

NAME
       uname - get name and information about current kernel

SYNOPSIS
       #include <sys/utsname.h>

       int uname(struct utsname *buf);

DESCRIPTION
       uname()  returns  system information in the structure pointed to by buf.  The utsname struct is
       defined in <sys/utsname.h>:

           struct utsname {
               char sysname[];    /* Operating system name (e.g., "Linux") */
               char nodename[];   /* Name within "some implementation-defined
                                     network" */
               char release[];    /* Operating system release (e.g., "2.6.28") */
               char version[];    /* Operating system version */
               char machine[];    /* Hardware identifier */
           #ifdef _GNU_SOURCE
               char domainname[]; /* NIS or YP domain name */
           #endif
           };

       The length of the arrays in a struct utsname is unspecified (see NOTES); the fields are  termi‐
       nated by a null byte ('\0').

RETURN VALUE
       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

2. sample

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <sys/utsname.h>

int main(int argc, char **argv)
{

        struct utsname kernelVersionBuffer;
        //memset(&kernelVersionBuffer, 0, sizeof(kernelVersionBuffer));
        int ret = uname(&kernelVersionBuffer);
        if(ret < 0)
        {
                printf("errno:%d errMsg:%s\n", errno, strerror(errno));
                return -1;
        }

        printf(" sysName:%s\n nodeName:%s\n release:%s\n version:%s\n machine:%s\n domainName:%s\n", \
                kernelVersionBuffer.sysname,\
                kernelVersionBuffer.nodename,\
                kernelVersionBuffer.release,\
                kernelVersionBuffer.version,\
                kernelVersionBuffer.machine,\
                kernelVersionBuffer.domainname);

        return 0;
}

3. compile

$ gcc kernelVersion.c -o getKernelVersion

4. out

$ ./getKernelVersion
 sysName:Linux
 nodeName:ubuntu
 release:4.15.0-142-generic
 version:#146~16.04.1-Ubuntu SMP Tue Apr 13 09:27:15 UTC 2021
 machine:x86_64
 domainName:(none)
  
$ uname -a
Linux ubuntu 4.15.0-142-generic #146~16.04.1-Ubuntu SMP Tue Apr 13 09:27:15 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux