You can do something like this to read 10 bytes:
char buffer[10];
read(STDIN_FILENO, buffer, 10);
remember read() doesn’t add ‘ ’ to terminate to make it string (just gives raw buffer).
To read 1 byte at a time:
char ch;
while(read(STDIN_FILENO, &ch, 1) > 0)
{
//do stuff
}
and don’t forget to #include
There are three standard POSIX file descriptors, corresponding to the three standard streams, which presumably every process should expect to have:
Integer value Name
0 Standard input (stdin)
1 Standard output (stdout)
2 Standard error (stderr)
So instead STDIN_FILENO you can use 0.
Edit:
In Linux System you can find this using following command:
$ sudo grep ‘STDIN_FILENO’ /usr/include/* -R | grep ‘define’
/usr/include/unistd.h:#define STDIN_FILENO 0 /* Standard input. */
Notice the comment /* Standard input. */
From the man read:
#include
ssize_t read(int fd, void *buf, size_t count);
Input parameters:
int fd file descriptor is an integer and not a file pointer. The file descriptor for stdin is 0
void *buf pointer to buffer to store characters read by the read function
size_t count maximum number of characters to read
So you can read character by character with the following code:
char buf[1];
while(read(0, buf, sizeof(buf))>0) {
// read() here read from stdin charachter by character
// the buf[0] contains the character got by read()
….
}