linux 计算CPU使用率（C代码）

int getcpuutilization(char *cpuutilization)

{

    int sum1[2]={0};

    int sum2[2]={0};

    int i=0;

    for(i=0;i<2;i++){

        if(i==1)

        {

                sleep(3);

        }

        FILE *stream1=NULL;

        FILE *stream2=NULL;

        FILE *stream3=NULL;

        FILE *stream4=NULL;

        FILE *stream5=NULL;

        FILE *stream6=NULL;

        FILE *stream7=NULL;

        FILE *stream8=NULL;

        FILE *stream9=NULL;

        char COMMAND1[OSNAMESZ]="cat /proc/stat | sed -n 1p | awk '{print $2}'";

        char COMMAND2[OSNAMESZ]="cat /proc/stat | sed -n 1p | awk '{print $3}'";

        char COMMAND3[OSNAMESZ]="cat /proc/stat | sed -n 1p | awk '{print $4}'";

        char COMMAND4[OSNAMESZ]="cat /proc/stat | sed -n 1p | awk '{print $5}'";

        char COMMAND5[OSNAMESZ]="cat /proc/stat | sed -n 1p | awk '{print $6}'";

        char COMMAND6[OSNAMESZ]="cat /proc/stat | sed -n 1p | awk '{print $7}'";

        char COMMAND7[OSNAMESZ]="cat /proc/stat | sed -n 1p | awk '{print $8}'";

        char COMMAND8[OSNAMESZ]="cat /proc/stat | sed -n 1p | awk '{print $9}'";

        char COMMAND9[OSNAMESZ]="cat /proc/stat | sed -n 1p | awk '{print $10}'";

        char buff1[OSNAMESZ]={0};

        char buff2[OSNAMESZ]={0};

        char buff3[OSNAMESZ]={0};

        char buff4[OSNAMESZ]={0};

        char buff5[OSNAMESZ]={0};

        char buff6[OSNAMESZ]={0};

        char buff7[OSNAMESZ]={0};

        char buff8[OSNAMESZ]={0};

        char buff9[OSNAMESZ]={0};

        int cpudata1;

        int cpudata2;

        int cpudata3;

        int cpudata4;

        int cpudata5;

        int cpudata6;

        int cpudata7;

        int cpudata8;

        int cpudata9;

        stream1=popen(COMMAND1,"r");

        signal(SIGCHLD,SIG_IGN);

        stream2=popen(COMMAND2,"r");

        signal(SIGCHLD,SIG_IGN);

        stream3=popen(COMMAND3,"r");

        signal(SIGCHLD,SIG_IGN);

        stream4=popen(COMMAND4,"r");

        signal(SIGCHLD,SIG_IGN);

        stream5=popen(COMMAND5,"r");

        signal(SIGCHLD,SIG_IGN);

        stream6=popen(COMMAND6,"r");

        signal(SIGCHLD,SIG_IGN);

        stream7=popen(COMMAND7,"r");

        signal(SIGCHLD,SIG_IGN);

        stream8=popen(COMMAND8,"r");

        signal(SIGCHLD,SIG_IGN);

        stream9=popen(COMMAND9,"r");

        signal(SIGCHLD,SIG_IGN);

        if(!stream1 || !stream2 || !stream3 || !stream4 || !stream5 || !stream6 || !stream7 || !stream8 || !stream9)

        {

                return -1;

        }

        fread(buff1,sizeof(char),OSNAMESZ,stream1);

        pclose(stream1);

        fread(buff2,sizeof(char),OSNAMESZ,stream2);

        pclose(stream2);

        fread(buff3,sizeof(char),OSNAMESZ,stream3);

        pclose(stream3);

        fread(buff4,sizeof(char),OSNAMESZ,stream4);

        pclose(stream4);

        fread(buff5,sizeof(char),OSNAMESZ,stream5);

        pclose(stream5);

        fread(buff6,sizeof(char),OSNAMESZ,stream6);

        pclose(stream6);

        fread(buff7,sizeof(char),OSNAMESZ,stream7);

        pclose(stream7);

        fread(buff8,sizeof(char),OSNAMESZ,stream8);

        pclose(stream8);

        fread(buff9,sizeof(char),OSNAMESZ,stream9);

        pclose(stream9);

        if(strlen(buff1)==0 || strlen(buff2)==0 || strlen(buff3)==0 || strlen(buff4)==0 || strlen(buff5)==0 || strlen(buff6)==0 || strlen(buff7)==0 || strlen(buff8)==0 || strlen(buff9)==0)

        {

                return -1;

        }

        cpudata1=atoi(buff1);

        cpudata2=atoi(buff2);

        cpudata3=atoi(buff3);

        cpudata4=atoi(buff4);

        cpudata5=atoi(buff5);

        cpudata6=atoi(buff6);

        cpudata7=atoi(buff7);

        cpudata8=atoi(buff8);

        cpudata9=atoi(buff9);

        sum1[i]=cpudata1+cpudata2+cpudata3;

        sum2[i]=cpudata1+cpudata2+cpudata3+cpudata4+cpudata5+cpudata6+cpudata7+cpudata8+cpudata9;

    }

    sprintf(cpuutilization,"%0.1f",(float)(sum1[1]-sum1[0])/(sum2[1]-sum2[0])*100);

    return 0;

}

完！！