Function prototype
int open (char * pathname, int how);
path name pathname open method how
Three ways to open
O_RDONLY Read only
O_WRONLY Write only
O_RDWR Read and write
There are these three macro definitions in <fcntl.h>
return value
-1 Open failed
int Successful return returns a file descriptor
Code
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
int main(int argc, char *argv[])
{
int fd = -1;
fd = open("/home/zzh35/TestWho/1.txt", O_RDONLY);
if(-1 != fd)
{
printf("%d\n",fd);
}
else if(-1 == fd)
{
printf("-1 Open fail\n");
}
return 0;
}
The operation result returned a file descriptor 3
details