C语言之 read
read
is a system call used to read data into a buffer.
Required Include Files
#include <unistd.h>
Function Definition
ssize_t read(int fildes, void *buf, size_t nbytes);
Field | Description |
---|---|
int fildes | The file descriptor of where to read the input. You can either use a file descriptor obtained from the open system call, or you can use 0, 1, or 2, to refer to standard input, standard output, or standard error, respectively. |
const void *buf | A character array where the read content will be stored. |
size_t nbytes | The number of bytes to read before truncating the data. If the data to be read is smaller than nbytes, all data is saved in the buffer. |
return value | Returns the number of bytes that were read. If value is negative, then the system call returned an error. |
Code Snippet
#include <unistd.h>
int main()
{
char data[128];
if(read(0, data, 128) < 0)
write(2, "An error occurred in the read.\n", 31);
exit(0);
}