… | |
… | |
54 | 2. fork |
54 | 2. fork |
55 | 3. in the parent, continue business as usual, done |
55 | 3. in the parent, continue business as usual, done |
56 | 4. in the child, destroy all ready and pending requests and free the |
56 | 4. in the child, destroy all ready and pending requests and free the |
57 | memory used by the worker threads. This gives you a fully empty |
57 | memory used by the worker threads. This gives you a fully empty |
58 | libeio queue. |
58 | libeio queue. |
|
|
59 | |
|
|
60 | Note, however, since libeio does use threads, thr above guarantee doesn't |
|
|
61 | cover your libc, for example, malloc and other libc functions are not |
|
|
62 | fork-safe, so there is very little you can do after a fork, and in fatc, |
|
|
63 | the above might crash, and thus change. |
59 | |
64 | |
60 | =head1 INITIALISATION/INTEGRATION |
65 | =head1 INITIALISATION/INTEGRATION |
61 | |
66 | |
62 | Before you can call any eio functions you first have to initialise the |
67 | Before you can call any eio functions you first have to initialise the |
63 | library. The library integrates into any event loop, but can also be used |
68 | library. The library integrates into any event loop, but can also be used |
… | |
… | |
215 | C<eio_poll>). |
220 | C<eio_poll>). |
216 | |
221 | |
217 | =back |
222 | =back |
218 | |
223 | |
219 | |
224 | |
220 | =head1 ANATOMY OF AN EIO REQUEST |
225 | =head1 HIGH LEVEL REQUEST API |
|
|
226 | |
|
|
227 | Libeio has both a high-level API, which consists of calling a request |
|
|
228 | function with a callback to be called on completion, and a low-level API |
|
|
229 | where you fill out request structures and submit them. |
|
|
230 | |
|
|
231 | This section describes the high-level API. |
|
|
232 | |
|
|
233 | =head2 REQUEST SUBMISSION AND RESULT PROCESSING |
|
|
234 | |
|
|
235 | You submit a request by calling the relevant C<eio_TYPE> function with the |
|
|
236 | required parameters, a callback of type C<int (*eio_cb)(eio_req *req)> |
|
|
237 | (called C<eio_cb> below) and a freely usable C<void *data> argument. |
|
|
238 | |
|
|
239 | The return value will either be 0 |
|
|
240 | |
|
|
241 | The callback will be called with an C<eio_req *> which contains the |
|
|
242 | results of the request. The members you can access inside that structure |
|
|
243 | vary from request to request, except for: |
|
|
244 | |
|
|
245 | =over 4 |
|
|
246 | |
|
|
247 | =item C<ssize_t result> |
|
|
248 | |
|
|
249 | This contains the result value from the call (usually the same as the |
|
|
250 | syscall of the same name). |
|
|
251 | |
|
|
252 | =item C<int errorno> |
|
|
253 | |
|
|
254 | This contains the value of C<errno> after the call. |
|
|
255 | |
|
|
256 | =item C<void *data> |
|
|
257 | |
|
|
258 | The C<void *data> member simply stores the value of the C<data> argument. |
|
|
259 | |
|
|
260 | =back |
|
|
261 | |
|
|
262 | The return value of the callback is normally C<0>, which tells libeio to |
|
|
263 | continue normally. If a callback returns a nonzero value, libeio will |
|
|
264 | stop processing results (in C<eio_poll>) and will return the value to its |
|
|
265 | caller. |
|
|
266 | |
|
|
267 | Memory areas passed to libeio must stay valid as long as a request |
|
|
268 | executes, with the exception of paths, which are being copied |
|
|
269 | internally. Any memory libeio itself allocates will be freed after the |
|
|
270 | finish callback has been called. If you want to manage all memory passed |
|
|
271 | to libeio yourself you can use the low-level API. |
|
|
272 | |
|
|
273 | For example, to open a file, you could do this: |
|
|
274 | |
|
|
275 | static int |
|
|
276 | file_open_done (eio_req *req) |
|
|
277 | { |
|
|
278 | if (req->result < 0) |
|
|
279 | { |
|
|
280 | /* open() returned -1 */ |
|
|
281 | errno = req->errorno; |
|
|
282 | perror ("open"); |
|
|
283 | } |
|
|
284 | else |
|
|
285 | { |
|
|
286 | int fd = req->result; |
|
|
287 | /* now we have the new fd in fd */ |
|
|
288 | } |
|
|
289 | |
|
|
290 | return 0; |
|
|
291 | } |
|
|
292 | |
|
|
293 | /* the first three arguments are passed to open(2) */ |
|
|
294 | /* the remaining are priority, callback and data */ |
|
|
295 | if (!eio_open ("/etc/passwd", O_RDONLY, 0, 0, file_open_done, 0)) |
|
|
296 | abort (); /* something ent wrong, we will all die!!! */ |
|
|
297 | |
|
|
298 | Note that you additionally need to call C<eio_poll> when the C<want_cb> |
|
|
299 | indicates that requests are ready to be processed. |
|
|
300 | |
|
|
301 | =head2 AVAILABLE REQUESTS |
|
|
302 | |
|
|
303 | The following request functions are available. I<All> of them return the |
|
|
304 | C<eio_req *> on success and C<0> on failure, and I<all> of them have the |
|
|
305 | same three trailing arguments: C<pri>, C<cb> and C<data>. The C<cb> is |
|
|
306 | mandatory, but in most cases, you pass in C<0> as C<pri> and C<0> or some |
|
|
307 | custom data value as C<data>. |
|
|
308 | |
|
|
309 | =head3 POSIX API WRAPPERS |
|
|
310 | |
|
|
311 | These requests simply wrap the POSIX call of the same name, with the same |
|
|
312 | arguments: |
|
|
313 | |
|
|
314 | =over 4 |
|
|
315 | |
|
|
316 | =item eio_open (const char *path, int flags, mode_t mode, int pri, eio_cb cb, void *data) |
|
|
317 | |
|
|
318 | =item eio_utime (const char *path, eio_tstamp atime, eio_tstamp mtime, int pri, eio_cb cb, void *data) |
|
|
319 | |
|
|
320 | =item eio_truncate (const char *path, off_t offset, int pri, eio_cb cb, void *data) |
|
|
321 | |
|
|
322 | =item eio_chown (const char *path, uid_t uid, gid_t gid, int pri, eio_cb cb, void *data) |
|
|
323 | |
|
|
324 | =item eio_chmod (const char *path, mode_t mode, int pri, eio_cb cb, void *data) |
|
|
325 | |
|
|
326 | =item eio_mkdir (const char *path, mode_t mode, int pri, eio_cb cb, void *data) |
|
|
327 | |
|
|
328 | =item eio_rmdir (const char *path, int pri, eio_cb cb, void *data) |
|
|
329 | |
|
|
330 | =item eio_unlink (const char *path, int pri, eio_cb cb, void *data) |
|
|
331 | |
|
|
332 | =item eio_readlink (const char *path, int pri, eio_cb cb, void *data) /* result=ptr2 allocated dynamically */ |
|
|
333 | |
|
|
334 | =item eio_stat (const char *path, int pri, eio_cb cb, void *data) /* stat buffer=ptr2 allocated dynamically */ |
|
|
335 | |
|
|
336 | =item eio_lstat (const char *path, int pri, eio_cb cb, void *data) /* stat buffer=ptr2 allocated dynamically */ |
|
|
337 | |
|
|
338 | =item eio_statvfs (const char *path, int pri, eio_cb cb, void *data) /* stat buffer=ptr2 allocated dynamically */ |
|
|
339 | |
|
|
340 | =item eio_mknod (const char *path, mode_t mode, dev_t dev, int pri, eio_cb cb, void *data) |
|
|
341 | |
|
|
342 | =item eio_link (const char *path, const char *new_path, int pri, eio_cb cb, void *data) |
|
|
343 | |
|
|
344 | =item eio_symlink (const char *path, const char *new_path, int pri, eio_cb cb, void *data) |
|
|
345 | |
|
|
346 | =item eio_rename (const char *path, const char *new_path, int pri, eio_cb cb, void *data) |
|
|
347 | |
|
|
348 | =item eio_msync (void *addr, size_t length, int flags, int pri, eio_cb cb, void *data) |
|
|
349 | |
|
|
350 | =item eio_mlock (void *addr, size_t length, int pri, eio_cb cb, void *data) |
|
|
351 | |
|
|
352 | =item eio_mlockall (int flags, int pri, eio_cb cb, void *data) |
|
|
353 | |
|
|
354 | =item eio_close (int fd, int pri, eio_cb cb, void *data) |
|
|
355 | |
|
|
356 | =item eio_sync (int pri, eio_cb cb, void *data) |
|
|
357 | |
|
|
358 | =item eio_fsync (int fd, int pri, eio_cb cb, void *data) |
|
|
359 | |
|
|
360 | =item eio_fdatasync (int fd, int pri, eio_cb cb, void *data) |
|
|
361 | |
|
|
362 | =item eio_futime (int fd, eio_tstamp atime, eio_tstamp mtime, int pri, eio_cb cb, void *data) |
|
|
363 | |
|
|
364 | =item eio_ftruncate (int fd, off_t offset, int pri, eio_cb cb, void *data) |
|
|
365 | |
|
|
366 | =item eio_fchmod (int fd, mode_t mode, int pri, eio_cb cb, void *data) |
|
|
367 | |
|
|
368 | =item eio_fchown (int fd, uid_t uid, gid_t gid, int pri, eio_cb cb, void *data) |
|
|
369 | |
|
|
370 | =item eio_dup2 (int fd, int fd2, int pri, eio_cb cb, void *data) |
|
|
371 | |
|
|
372 | These have the same semantics as the syscall of the same name, their |
|
|
373 | return value is available as C<< req->result >> later. |
|
|
374 | |
|
|
375 | =item eio_read (int fd, void *buf, size_t length, off_t offset, int pri, eio_cb cb, void *data) |
|
|
376 | |
|
|
377 | =item eio_write (int fd, void *buf, size_t length, off_t offset, int pri, eio_cb cb, void *data) |
|
|
378 | |
|
|
379 | These two requests are called C<read> and C<write>, but actually wrap |
|
|
380 | C<pread> and C<pwrite>. On systems that lack these calls (such as cygwin), |
|
|
381 | libeio uses lseek/read_or_write/lseek and a mutex to serialise the |
|
|
382 | requests, so all these requests run serially and do not disturb each |
|
|
383 | other. However, they still disturb the file offset while they run, so it's |
|
|
384 | not safe to call these functions concurrently with non-libeio functions on |
|
|
385 | the same fd on these systems. |
|
|
386 | |
|
|
387 | Not surprisingly, pread and pwrite are not thread-safe on Darwin (OS/X), |
|
|
388 | so it is advised not to submit multiple requests on the same fd on this |
|
|
389 | horrible pile of garbage. |
|
|
390 | |
|
|
391 | =item eio_fstat (int fd, int pri, eio_cb cb, void *data) |
|
|
392 | |
|
|
393 | Stats a file - if C<< req->result >> indicates success, then you can |
|
|
394 | access the C<struct stat>-like structure via C<< req->ptr2 >>: |
|
|
395 | |
|
|
396 | EIO_STRUCT_STAT *statdata = (EIO_STRUCT_STAT *)req->ptr2; |
|
|
397 | |
|
|
398 | =item eio_fstatvfs (int fd, int pri, eio_cb cb, void *data) /* stat buffer=ptr2 allocated dynamically */ |
|
|
399 | |
|
|
400 | Stats a filesystem - if C<< req->result >> indicates success, then you can |
|
|
401 | access the C<struct statvfs>-like structure via C<< req->ptr2 >>: |
|
|
402 | |
|
|
403 | EIO_STRUCT_STATVFS *statdata = (EIO_STRUCT_STATVFS *)req->ptr2; |
|
|
404 | |
|
|
405 | =back |
|
|
406 | |
|
|
407 | =head3 READING DIRECTORIES |
|
|
408 | |
|
|
409 | Reading directories sounds simple, but can be rather demanding, especially |
|
|
410 | if you want to do stuff such as traversing a diretcory hierarchy or |
|
|
411 | processing all files in a directory. Libeio can assist thess complex tasks |
|
|
412 | with it's C<eio_readdir> call. |
|
|
413 | |
|
|
414 | =over 4 |
|
|
415 | |
|
|
416 | =item eio_readdir (const char *path, int flags, int pri, eio_cb cb, void *data) |
|
|
417 | |
|
|
418 | This is a very complex call. It basically reads through a whole directory |
|
|
419 | (via the C<opendir>, C<readdir> and C<closedir> calls) and returns either |
|
|
420 | the names or an array of C<struct eio_dirent>, depending on the C<flags> |
|
|
421 | argument. |
|
|
422 | |
|
|
423 | The C<< req->result >> indicates either the number of files found, or |
|
|
424 | C<-1> on error. On success, zero-terminated names can be found as C<< req->ptr2 >>, |
|
|
425 | and C<struct eio_dirents>, if requested by C<flags>, can be found via C<< |
|
|
426 | req->ptr1 >>. |
|
|
427 | |
|
|
428 | Here is an example that prints all the names: |
|
|
429 | |
|
|
430 | int i; |
|
|
431 | char *names = (char *)req->ptr2; |
|
|
432 | |
|
|
433 | for (i = 0; i < req->result; ++i) |
|
|
434 | { |
|
|
435 | printf ("name #%d: %s\n", i, names); |
|
|
436 | |
|
|
437 | /* move to next name */ |
|
|
438 | names += strlen (names) + 1; |
|
|
439 | } |
|
|
440 | |
|
|
441 | Pseudo-entries such as F<.> and F<..> are never returned by C<eio_readdir>. |
|
|
442 | |
|
|
443 | C<flags> can be any combination of: |
|
|
444 | |
|
|
445 | =over 4 |
|
|
446 | |
|
|
447 | =item EIO_READDIR_DENTS |
|
|
448 | |
|
|
449 | If this flag is specified, then, in addition to the names in C<ptr2>, |
|
|
450 | also an array of C<struct eio_dirent> is returned, in C<ptr1>. A C<struct |
|
|
451 | eio_dirent> looks like this: |
|
|
452 | |
|
|
453 | struct eio_dirent |
|
|
454 | { |
|
|
455 | int nameofs; /* offset of null-terminated name string in (char *)req->ptr2 */ |
|
|
456 | unsigned short namelen; /* size of filename without trailing 0 */ |
|
|
457 | unsigned char type; /* one of EIO_DT_* */ |
|
|
458 | signed char score; /* internal use */ |
|
|
459 | ino_t inode; /* the inode number, if available, otherwise unspecified */ |
|
|
460 | }; |
|
|
461 | |
|
|
462 | The only members you normally would access are C<nameofs>, which is the |
|
|
463 | byte-offset from C<ptr2> to the start of the name, C<namelen> and C<type>. |
|
|
464 | |
|
|
465 | C<type> can be one of: |
|
|
466 | |
|
|
467 | C<EIO_DT_UNKNOWN> - if the type is not known (very common) and you have to C<stat> |
|
|
468 | the name yourself if you need to know, |
|
|
469 | one of the "standard" POSIX file types (C<EIO_DT_REG>, C<EIO_DT_DIR>, C<EIO_DT_LNK>, |
|
|
470 | C<EIO_DT_FIFO>, C<EIO_DT_SOCK>, C<EIO_DT_CHR>, C<EIO_DT_BLK>) |
|
|
471 | or some OS-specific type (currently |
|
|
472 | C<EIO_DT_MPC> - multiplexed char device (v7+coherent), |
|
|
473 | C<EIO_DT_NAM> - xenix special named file, |
|
|
474 | C<EIO_DT_MPB> - multiplexed block device (v7+coherent), |
|
|
475 | C<EIO_DT_NWK> - HP-UX network special, |
|
|
476 | C<EIO_DT_CMP> - VxFS compressed, |
|
|
477 | C<EIO_DT_DOOR> - solaris door, or |
|
|
478 | C<EIO_DT_WHT>). |
|
|
479 | |
|
|
480 | This example prints all names and their type: |
|
|
481 | |
|
|
482 | int i; |
|
|
483 | struct eio_dirent *ents = (struct eio_dirent *)req->ptr1; |
|
|
484 | char *names = (char *)req->ptr2; |
|
|
485 | |
|
|
486 | for (i = 0; i < req->result; ++i) |
|
|
487 | { |
|
|
488 | struct eio_dirent *ent = ents + i; |
|
|
489 | char *name = names + ent->nameofs; |
|
|
490 | |
|
|
491 | printf ("name #%d: %s (type %d)\n", i, name, ent->type); |
|
|
492 | } |
|
|
493 | |
|
|
494 | =item EIO_READDIR_DIRS_FIRST |
|
|
495 | |
|
|
496 | When this flag is specified, then the names will be returned in an order |
|
|
497 | where likely directories come first, in optimal C<stat> order. This is |
|
|
498 | useful when you need to quickly find directories, or you want to find all |
|
|
499 | directories while avoiding to stat() each entry. |
|
|
500 | |
|
|
501 | If the system returns type information in readdir, then this is used |
|
|
502 | to find directories directly. Otherwise, likely directories are names |
|
|
503 | beginning with ".", or otherwise names with no dots, of which names with |
|
|
504 | short names are tried first. |
|
|
505 | |
|
|
506 | =item EIO_READDIR_STAT_ORDER |
|
|
507 | |
|
|
508 | When this flag is specified, then the names will be returned in an order |
|
|
509 | suitable for stat()'ing each one. That is, when you plan to stat() |
|
|
510 | all files in the given directory, then the returned order will likely |
|
|
511 | be fastest. |
|
|
512 | |
|
|
513 | If both this flag and C<EIO_READDIR_DIRS_FIRST> are specified, then |
|
|
514 | the likely dirs come first, resulting in a less optimal stat order. |
|
|
515 | |
|
|
516 | =item EIO_READDIR_FOUND_UNKNOWN |
|
|
517 | |
|
|
518 | This flag should not be specified when calling C<eio_readdir>. Instead, |
|
|
519 | it is being set by C<eio_readdir> (you can access the C<flags> via C<< |
|
|
520 | req->int1 >>, when any of the C<type>'s found were C<EIO_DT_UNKNOWN>. The |
|
|
521 | absense of this flag therefore indicates that all C<type>'s are known, |
|
|
522 | which can be used to speed up some algorithms. |
|
|
523 | |
|
|
524 | A typical use case would be to identify all subdirectories within a |
|
|
525 | directory - you would ask C<eio_readdir> for C<EIO_READDIR_DIRS_FIRST>. If |
|
|
526 | then this flag is I<NOT> set, then all the entries at the beginning of the |
|
|
527 | returned array of type C<EIO_DT_DIR> are the directories. Otherwise, you |
|
|
528 | should start C<stat()>'ing the entries starting at the beginning of the |
|
|
529 | array, stopping as soon as you found all directories (the count can be |
|
|
530 | deduced by the link count of the directory). |
|
|
531 | |
|
|
532 | =back |
|
|
533 | |
|
|
534 | =back |
|
|
535 | |
|
|
536 | =head3 OS-SPECIFIC CALL WRAPPERS |
|
|
537 | |
|
|
538 | These wrap OS-specific calls (usually Linux ones), and might or might not |
|
|
539 | be emulated on other operating systems. Calls that are not emulated will |
|
|
540 | return C<-1> and set C<errno> to C<ENOSYS>. |
|
|
541 | |
|
|
542 | =over 4 |
|
|
543 | |
|
|
544 | =item eio_sendfile (int out_fd, int in_fd, off_t in_offset, size_t length, int pri, eio_cb cb, void *data) |
|
|
545 | |
|
|
546 | Wraps the C<sendfile> syscall. The arguments follow the Linux version, but |
|
|
547 | libeio supports and will use similar calls on FreeBSD, HP/UX, Solaris and |
|
|
548 | Darwin. |
|
|
549 | |
|
|
550 | If the OS doesn't support some sendfile-like call, or the call fails, |
|
|
551 | indicating support for the given file descriptor type (for example, |
|
|
552 | Linux's sendfile might not support file to file copies), then libeio will |
|
|
553 | emulate the call in userspace, so there are almost no limitations on its |
|
|
554 | use. |
|
|
555 | |
|
|
556 | =item eio_readahead (int fd, off_t offset, size_t length, int pri, eio_cb cb, void *data) |
|
|
557 | |
|
|
558 | Calls C<readahead(2)>. If the syscall is missing, then the call is |
|
|
559 | emulated by simply reading the data (currently in 64kiB chunks). |
|
|
560 | |
|
|
561 | =item eio_sync_file_range (int fd, off_t offset, size_t nbytes, unsigned int flags, int pri, eio_cb cb, void *data) |
|
|
562 | |
|
|
563 | Calls C<sync_file_range>. If the syscall is missing, then this is the same |
|
|
564 | as calling C<fdatasync>. |
|
|
565 | |
|
|
566 | =back |
|
|
567 | |
|
|
568 | =head3 LIBEIO-SPECIFIC REQUESTS |
|
|
569 | |
|
|
570 | These requests are specific to libeio and do not correspond to any OS call. |
|
|
571 | |
|
|
572 | =over 4 |
|
|
573 | |
|
|
574 | =item eio_mtouch (void *addr, size_t length, int flags, int pri, eio_cb cb, void *data) |
|
|
575 | |
|
|
576 | =item eio_custom (void (*)(eio_req *) execute, int pri, eio_cb cb, void *data) |
|
|
577 | |
|
|
578 | Executes a custom request, i.e., a user-specified callback. |
|
|
579 | |
|
|
580 | The callback gets the C<eio_req *> as parameter and is expected to read |
|
|
581 | and modify any request-specific members. Specifically, it should set C<< |
|
|
582 | req->result >> to the result value, just like other requests. |
|
|
583 | |
|
|
584 | Here is an example that simply calls C<open>, like C<eio_open>, but it |
|
|
585 | uses the C<data> member as filename and uses a hardcoded C<O_RDONLY>. If |
|
|
586 | you want to pass more/other parameters, you either need to pass some |
|
|
587 | struct or so via C<data> or provide your own wrapper using the low-level |
|
|
588 | API. |
|
|
589 | |
|
|
590 | static int |
|
|
591 | my_open_done (eio_req *req) |
|
|
592 | { |
|
|
593 | int fd = req->result; |
|
|
594 | |
|
|
595 | return 0; |
|
|
596 | } |
|
|
597 | |
|
|
598 | static void |
|
|
599 | my_open (eio_req *req) |
|
|
600 | { |
|
|
601 | req->result = open (req->data, O_RDONLY); |
|
|
602 | } |
|
|
603 | |
|
|
604 | eio_custom (my_open, 0, my_open_done, "/etc/passwd"); |
|
|
605 | |
|
|
606 | =item eio_busy (eio_tstamp delay, int pri, eio_cb cb, void *data) |
|
|
607 | |
|
|
608 | This is a a request that takes C<delay> seconds to execute, but otherwise |
|
|
609 | does nothing - it simply puts one of the worker threads to sleep for this |
|
|
610 | long. |
|
|
611 | |
|
|
612 | This request can be used to artificially increase load, e.g. for debugging |
|
|
613 | or benchmarking reasons. |
|
|
614 | |
|
|
615 | =item eio_nop (int pri, eio_cb cb, void *data) |
|
|
616 | |
|
|
617 | This request does nothing, except go through the whole request cycle. This |
|
|
618 | can be used to measure latency or in some cases to simplify code, but is |
|
|
619 | not really of much use. |
|
|
620 | |
|
|
621 | =back |
|
|
622 | |
|
|
623 | =head3 GROUPING AND LIMITING REQUESTS |
221 | |
624 | |
222 | #TODO |
625 | #TODO |
223 | |
626 | |
|
|
627 | /*****************************************************************************/ |
|
|
628 | /* groups */ |
224 | |
629 | |
|
|
630 | eio_req *eio_grp (eio_cb cb, void *data); |
|
|
631 | void eio_grp_feed (eio_req *grp, void (*feed)(eio_req *req), int limit); |
|
|
632 | void eio_grp_limit (eio_req *grp, int limit); |
|
|
633 | void eio_grp_add (eio_req *grp, eio_req *req); |
|
|
634 | void eio_grp_cancel (eio_req *grp); /* cancels all sub requests but not the group */ |
|
|
635 | |
|
|
636 | |
|
|
637 | =back |
|
|
638 | |
|
|
639 | |
225 | =head1 HIGH LEVEL REQUEST API |
640 | =head1 LOW LEVEL REQUEST API |
226 | |
641 | |
227 | #TODO |
642 | #TODO |
228 | |
643 | |
229 | =back |
|
|
230 | |
644 | |
|
|
645 | =head1 ANATOMY AND LIFETIME OF AN EIO REQUEST |
231 | |
646 | |
232 | =head1 LOW LEVEL REQUEST API |
647 | A request is represented by a structure of type C<eio_req>. To initialise |
|
|
648 | it, clear it to all zero bytes: |
|
|
649 | |
|
|
650 | eio_req req; |
|
|
651 | |
|
|
652 | memset (&req, 0, sizeof (req)); |
|
|
653 | |
|
|
654 | A more common way to initialise a new C<eio_req> is to use C<calloc>: |
|
|
655 | |
|
|
656 | eio_req *req = calloc (1, sizeof (*req)); |
|
|
657 | |
|
|
658 | In either case, libeio neither allocates, initialises or frees the |
|
|
659 | C<eio_req> structure for you - it merely uses it. |
|
|
660 | |
|
|
661 | zero |
233 | |
662 | |
234 | #TODO |
663 | #TODO |
235 | |
664 | |
236 | =head1 EMBEDDING |
665 | =head1 EMBEDDING |
237 | |
666 | |