Linux exercises (read)

# Include <unistd. h> # include <stdlib. h> int main () {char buffer [128]; int nread; nread = read (0, buffer, 128); If (nread =-1) write (2, "A read error has occurred \ n", 26); If (write (1, buffer, nread ))! = Nread) write (2, "A write error has occurred \ n", 27); exit (0 );}

Function prototype:

# Include <unistd. h>

Size_t read (INT Fildes, const void * Buf, size_t nbytes );

 

Read () parameter 1: Same as write ()

Parameter 2: Read data

Parameter 3: size of the read data

 

Return Value:

Normally, the returned data size is nbytes.

If the return value is 0, no data is read, which may reach the end of the file.

-1 indicates an error occurred.