| read |
| Prototype: |
#include <unistd.h>
int read(int fd, char *buffer, int buf_len);
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| General Description: |
Read buf_len bytes from the fd file descriptor into the buffer. You can use this system call for sockets as well as files. However , this call does not provide as much control as the recv() system call. |
| Return Value: |
The number of bytes actually read. |
| Parameters |
| fd |
File (or socket) descriptor. |
| buffer |
The memory buffer to accept the read data. |
| buf_len |
The number of bytes to read and the number of legal bytes in the buffer. |
| Possible Errors |
| EINTR |
The call was interrupted by a signal before any data was read. |
| EAGAIN |
Non-blocking I/O has been selected using O_NONBLOCK and no data was immediately available for reading. |
| EIO |
I/O error. This will happen for example when the process is in a background process group, tries to read from its controlling tty, and either it is ignoring or blocking SIGTTIN or its process group is orphaned. It may also occur when there is a low-level I/O error while reading from a disk or tape. |
| EISDIR |
fd refers to a directory. |
| EBADF |
fd is not a valid file descriptor or is not open for reading. |
| EINVAL |
fd is attached to an object which is unsuitable for reading. |
| EFAULT |
buf is outside your accessible address space. |
| Examples |
int sockfd;
int bytes_read;
char buffer[1024];
/*---create socket & connect to server---*/
if ( (bytes_read = read(sockfd, buffer, sizeof(buffer))) < 0 )
perror("read");
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