unix/Linux 低級IO函數(shù)的用法read && write

lchjczw 2012-04-13

展開全文

簡單的讀一個文件：

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

int main(int argc,char **argv)
{
int fd = 0;
int pid = 0;
char buffer[20] = {'\0'};
char *read_buffer[20] = {'\0'};

//fd = open("/dev/hello",O_RDWR | O_CREAT | O_TRUNC);
fd = open("/dev/hello",O_RDONLY ); //| O_NONBLOCK);
printf("fd=%d\n",fd);
if(fd < 0) {
perror("/dev/hello");
return -1;
}

read(fd,read_buffer,sizeof(read_buffer)-1);
printf("read_buffer=%s\n",read_buffer);

close(fd);

return 0;
}

---

下面這個就是簡單的寫一個文件，
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

int main(int argc,char **argv)
{
int fd = 0;
int pid = 0;
char buffer[20] = {'\0'};
char write_buffer[20] = {'\0'};

strcpy(write_buffer,"zhanglinbao");

fd = open("/dev/hello",O_RDWR | O_CREAT | O_TRUNC);
//fd = open("/dev/hello",O_RDONLY);
printf("fd=%d\n",fd);
if(fd < 0) {
perror("/dev/hello");
return -1;
}

write(fd,write_buffer,sizeof(write_buffer)-1);

close(fd);

return 0;
}