The Android Open Source Project | 10e23ee | 2009-03-03 19:30:30 -0800 | [diff] [blame^] | 1 | /** |
| 2 | * @file op_deviceio.h |
| 3 | * Reading from a special device |
| 4 | * |
| 5 | * @remark Copyright 2002 OProfile authors |
| 6 | * @remark Read the file COPYING |
| 7 | * |
| 8 | * @author John Levon |
| 9 | * @author Philippe Elie |
| 10 | */ |
| 11 | |
| 12 | #ifndef OP_DEVICEIO_H |
| 13 | #define OP_DEVICEIO_H |
| 14 | |
| 15 | #ifdef __cplusplus |
| 16 | extern "C" { |
| 17 | #endif |
| 18 | |
| 19 | #include "op_types.h" |
| 20 | |
| 21 | #include <unistd.h> |
| 22 | |
| 23 | /** |
| 24 | * op_open_device - open a special char device for reading |
| 25 | * @param name file name of device file |
| 26 | * |
| 27 | * Open the special file name. Returns the file descriptor |
| 28 | * for the file or -1 on error. |
| 29 | */ |
| 30 | fd_t op_open_device(char const * name); |
| 31 | |
| 32 | /** |
| 33 | * op_read_device - read from a special char device |
| 34 | * @param devfd file descriptor of device |
| 35 | * @param buf buffer |
| 36 | * @param size size of buffer |
| 37 | * |
| 38 | * Read size bytes from a device into buffer buf. |
| 39 | * A seek to the start of the device file is done first |
| 40 | * then a read is requested in one go of size bytes. |
| 41 | * |
| 42 | * It is the caller's responsibility to do further op_read_device() |
| 43 | * calls if the number of bytes read is not what is requested |
| 44 | * (where this is applicable). |
| 45 | * |
| 46 | * The number of bytes read is returned, or a negative number |
| 47 | * on failure (in which case errno will be set). If the call is |
| 48 | * interrupted, then errno will be EINTR, and the client should |
| 49 | * arrange for re-starting the read if necessary. |
| 50 | */ |
| 51 | ssize_t op_read_device(fd_t devfd, void * buf, size_t size); |
| 52 | |
| 53 | #ifdef __cplusplus |
| 54 | } |
| 55 | #endif |
| 56 | |
| 57 | #endif /* OP_DEVICEIO_H */ |