fork/execvp
-----------------------------gre.c(生成十��文件)
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <string.h>
int foo(char *st)
{
char ch[10]={0};
int start=atoi(st);
printf("****************%d\n",start);
int fd,count=0;
char s[5]={0};
sprintf(ch,"%d.txt",start+1);
fd=open(ch,O_WRONLY|O_CREAT,0644);
if(fd<0){
perror("open somefile");
_exit(1);
}
start=start*10+1;
while(count<10)
{
sprintf(s,"%3d",start);
write(fd,s,strlen(s));
count++;
start++;
}
}
int main(int argc,char *argv[])
{
foo(argv[1]);
return 0;
}
---------------------------merger.c(�⑸�成的是��文件合��橐��)
#include <stdlib.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#define N 10
int main(void) {
int *p={0};
char *q={0};
int fd={0};
int fw=open("data.txt",O_RDWR|O_CREAT|O_TRUNC,0644);
int len=0,j;
char ch[50];
if(fw<0){
perror("open hello2");
exit(1);
}
for(j=0;j<N;j++)
{
sprintf(ch,"%d.txt",j+1);
fd=open(ch,O_RDONLY);
if(fd<0)
{
perror("open somefile");
_exit(1);
}
len+=lseek(fd,0,SEEK_END)+1;
close(fd);
}
lseek(fw,len-1,SEEK_END);
write(fw," ",1);
q=mmap(NULL,len,PROT_WRITE,MAP_SHARED,fw,0);
if(q==MAP_FAILED){
perror("mmap");
exit(1);
}
for(j=0;j<N;j++)
{
sprintf(ch,"%d.txt",j+1);
fd=open(ch,O_RDONLY);
if(fd<0)
{
perror("open somefile");
_exit(1);
}
len=lseek(fd,0,SEEK_END);
p=mmap(NULL,len,PROT_READ,MAP_SHARED,fd,0);
if(p==MAP_FAILED){
perror("mmap");
exit(1);
}
close(fd);
memcpy(q,p,len);
q=q+len;
memcpy(q,"\n",1);
q++;
munmap(p,len+1);
}
close(fw);
munmap(q,len);
return 0;
}
--------------------oper.c(通�^fork/execvp�绦幸陨喜僮�)
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <string.h>
int main(int argc,char *argv[])
{
int count=0;
char ch[20]={0};
int stat_val;
char *myargv[3]={0};
char *meargv[2]={0};
myargv[0]=malloc(10);
strcpy(myargv[0],"./gre");
meargv[0]=malloc(10);
strcpy(meargv[0],"./merger");
pid_t pid;
while(count<10)
{
pid=fork();
if(pid<0){
perror("fork");
exit(1);
}
printf("%d\n",pid);
if(pid==0)
{
sprintf(ch,"%d",count);
myargv[1]=malloc(5);
strcpy(myargv[1],ch);
execvp(myargv[0],myargv);
}
count++;
}
while(count>0)
{
wait(&stat_val);
count--;
}
pid=fork();
if(pid<0){
perror("fork");
exit(1);
}
printf("%d\n",pid);
if(pid==0)
execvp(meargv[0],meargv);
wait(&stat_val);
return 0;
}