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153 | |
153 | |
154 | You submit a request by calling the relevant C<eio_TYPE> function with the |
154 | You submit a request by calling the relevant C<eio_TYPE> function with the |
155 | required parameters, a callback of type C<int (*eio_cb)(eio_req *req)> |
155 | required parameters, a callback of type C<int (*eio_cb)(eio_req *req)> |
156 | (called C<eio_cb> below) and a freely usable C<void *data> argument. |
156 | (called C<eio_cb> below) and a freely usable C<void *data> argument. |
157 | |
157 | |
158 | The return value will either be 0 |
158 | The return value will either be 0, in case something went really wrong |
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159 | (which can basically only happen on very fatal errors, such as C<malloc> |
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160 | returning 0, which is rather unlikely), or a pointer to the newly-created |
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161 | and submitted C<eio_req *>. |
159 | |
162 | |
160 | The callback will be called with an C<eio_req *> which contains the |
163 | The callback will be called with an C<eio_req *> which contains the |
161 | results of the request. The members you can access inside that structure |
164 | results of the request. The members you can access inside that structure |
162 | vary from request to request, except for: |
165 | vary from request to request, except for: |
163 | |
166 | |
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226 | custom data value as C<data>. |
229 | custom data value as C<data>. |
227 | |
230 | |
228 | =head3 POSIX API WRAPPERS |
231 | =head3 POSIX API WRAPPERS |
229 | |
232 | |
230 | These requests simply wrap the POSIX call of the same name, with the same |
233 | These requests simply wrap the POSIX call of the same name, with the same |
231 | arguments: |
234 | arguments. If a function is not implemented by the OS and cannot be emulated |
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235 | in some way, then all of these return C<-1> and set C<errorno> to C<ENOSYS>. |
232 | |
236 | |
233 | =over 4 |
237 | =over 4 |
234 | |
238 | |
235 | =item eio_open (const char *path, int flags, mode_t mode, int pri, eio_cb cb, void *data) |
239 | =item eio_open (const char *path, int flags, mode_t mode, int pri, eio_cb cb, void *data) |
236 | |
240 | |
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241 | =item eio_truncate (const char *path, off_t offset, int pri, eio_cb cb, void *data) |
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242 | |
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243 | =item eio_chown (const char *path, uid_t uid, gid_t gid, int pri, eio_cb cb, void *data) |
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244 | |
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245 | =item eio_chmod (const char *path, mode_t mode, int pri, eio_cb cb, void *data) |
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246 | |
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247 | =item eio_mkdir (const char *path, mode_t mode, int pri, eio_cb cb, void *data) |
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248 | |
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249 | =item eio_rmdir (const char *path, int pri, eio_cb cb, void *data) |
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250 | |
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251 | =item eio_unlink (const char *path, int pri, eio_cb cb, void *data) |
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252 | |
237 | =item eio_utime (const char *path, eio_tstamp atime, eio_tstamp mtime, int pri, eio_cb cb, void *data) |
253 | =item eio_utime (const char *path, eio_tstamp atime, eio_tstamp mtime, int pri, eio_cb cb, void *data) |
238 | |
254 | |
239 | =item eio_truncate (const char *path, off_t offset, int pri, eio_cb cb, void *data) |
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240 | |
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241 | =item eio_chown (const char *path, uid_t uid, gid_t gid, int pri, eio_cb cb, void *data) |
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242 | |
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243 | =item eio_chmod (const char *path, mode_t mode, int pri, eio_cb cb, void *data) |
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244 | |
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245 | =item eio_mkdir (const char *path, mode_t mode, int pri, eio_cb cb, void *data) |
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246 | |
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247 | =item eio_rmdir (const char *path, int pri, eio_cb cb, void *data) |
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248 | |
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249 | =item eio_unlink (const char *path, int pri, eio_cb cb, void *data) |
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250 | |
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251 | =item eio_readlink (const char *path, int pri, eio_cb cb, void *data) /* result=ptr2 allocated dynamically */ |
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252 | |
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253 | =item eio_stat (const char *path, int pri, eio_cb cb, void *data) /* stat buffer=ptr2 allocated dynamically */ |
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254 | |
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255 | =item eio_lstat (const char *path, int pri, eio_cb cb, void *data) /* stat buffer=ptr2 allocated dynamically */ |
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256 | |
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257 | =item eio_statvfs (const char *path, int pri, eio_cb cb, void *data) /* stat buffer=ptr2 allocated dynamically */ |
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258 | |
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259 | =item eio_mknod (const char *path, mode_t mode, dev_t dev, int pri, eio_cb cb, void *data) |
255 | =item eio_mknod (const char *path, mode_t mode, dev_t dev, int pri, eio_cb cb, void *data) |
260 | |
256 | |
261 | =item eio_link (const char *path, const char *new_path, int pri, eio_cb cb, void *data) |
257 | =item eio_link (const char *path, const char *new_path, int pri, eio_cb cb, void *data) |
262 | |
258 | |
263 | =item eio_symlink (const char *path, const char *new_path, int pri, eio_cb cb, void *data) |
259 | =item eio_symlink (const char *path, const char *new_path, int pri, eio_cb cb, void *data) |
264 | |
260 | |
265 | =item eio_rename (const char *path, const char *new_path, int pri, eio_cb cb, void *data) |
261 | =item eio_rename (const char *path, const char *new_path, int pri, eio_cb cb, void *data) |
266 | |
262 | |
267 | =item eio_msync (void *addr, size_t length, int flags, int pri, eio_cb cb, void *data) |
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268 | |
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269 | =item eio_mlock (void *addr, size_t length, int pri, eio_cb cb, void *data) |
263 | =item eio_mlock (void *addr, size_t length, int pri, eio_cb cb, void *data) |
270 | |
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271 | =item eio_mlockall (int flags, int pri, eio_cb cb, void *data) |
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272 | |
264 | |
273 | =item eio_close (int fd, int pri, eio_cb cb, void *data) |
265 | =item eio_close (int fd, int pri, eio_cb cb, void *data) |
274 | |
266 | |
275 | =item eio_sync (int pri, eio_cb cb, void *data) |
267 | =item eio_sync (int pri, eio_cb cb, void *data) |
276 | |
268 | |
… | |
… | |
305 | |
297 | |
306 | Not surprisingly, pread and pwrite are not thread-safe on Darwin (OS/X), |
298 | Not surprisingly, pread and pwrite are not thread-safe on Darwin (OS/X), |
307 | so it is advised not to submit multiple requests on the same fd on this |
299 | so it is advised not to submit multiple requests on the same fd on this |
308 | horrible pile of garbage. |
300 | horrible pile of garbage. |
309 | |
301 | |
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302 | =item eio_mlockall (int flags, int pri, eio_cb cb, void *data) |
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303 | |
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304 | Like C<mlockall>, but the flag value constants are called |
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305 | C<EIO_MCL_CURRENT> and C<EIO_MCL_FUTURE>. |
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306 | |
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307 | =item eio_msync (void *addr, size_t length, int flags, int pri, eio_cb cb, void *data) |
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308 | |
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309 | Just like msync, except that the flag values are called C<EIO_MS_ASYNC>, |
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310 | C<EIO_MS_INVALIDATE> and C<EIO_MS_SYNC>. |
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311 | |
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312 | =item eio_readlink (const char *path, int pri, eio_cb cb, void *data) |
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313 | |
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314 | If successful, the path read by C<readlink(2)> can be accessed via C<< |
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315 | req->ptr2 >> and is I<NOT> null-terminated, with the length specified as |
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316 | C<< req->result >>. |
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317 | |
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318 | if (req->result >= 0) |
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319 | { |
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320 | char *target = strndup ((char *)req->ptr2, req->result); |
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321 | |
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322 | free (target); |
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323 | } |
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324 | |
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325 | =item eio_stat (const char *path, int pri, eio_cb cb, void *data) |
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326 | |
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327 | =item eio_lstat (const char *path, int pri, eio_cb cb, void *data) |
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328 | |
310 | =item eio_fstat (int fd, int pri, eio_cb cb, void *data) |
329 | =item eio_fstat (int fd, int pri, eio_cb cb, void *data) |
311 | |
330 | |
312 | Stats a file - if C<< req->result >> indicates success, then you can |
331 | Stats a file - if C<< req->result >> indicates success, then you can |
313 | access the C<struct stat>-like structure via C<< req->ptr2 >>: |
332 | access the C<struct stat>-like structure via C<< req->ptr2 >>: |
314 | |
333 | |
315 | EIO_STRUCT_STAT *statdata = (EIO_STRUCT_STAT *)req->ptr2; |
334 | EIO_STRUCT_STAT *statdata = (EIO_STRUCT_STAT *)req->ptr2; |
316 | |
335 | |
317 | =item eio_fstatvfs (int fd, int pri, eio_cb cb, void *data) /* stat buffer=ptr2 allocated dynamically */ |
336 | =item eio_statvfs (const char *path, int pri, eio_cb cb, void *data) |
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337 | |
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338 | =item eio_fstatvfs (int fd, int pri, eio_cb cb, void *data) |
318 | |
339 | |
319 | Stats a filesystem - if C<< req->result >> indicates success, then you can |
340 | Stats a filesystem - if C<< req->result >> indicates success, then you can |
320 | access the C<struct statvfs>-like structure via C<< req->ptr2 >>: |
341 | access the C<struct statvfs>-like structure via C<< req->ptr2 >>: |
321 | |
342 | |
322 | EIO_STRUCT_STATVFS *statdata = (EIO_STRUCT_STATVFS *)req->ptr2; |
343 | EIO_STRUCT_STATVFS *statdata = (EIO_STRUCT_STATVFS *)req->ptr2; |
… | |
… | |
338 | (via the C<opendir>, C<readdir> and C<closedir> calls) and returns either |
359 | (via the C<opendir>, C<readdir> and C<closedir> calls) and returns either |
339 | the names or an array of C<struct eio_dirent>, depending on the C<flags> |
360 | the names or an array of C<struct eio_dirent>, depending on the C<flags> |
340 | argument. |
361 | argument. |
341 | |
362 | |
342 | The C<< req->result >> indicates either the number of files found, or |
363 | The C<< req->result >> indicates either the number of files found, or |
343 | C<-1> on error. On success, zero-terminated names can be found as C<< req->ptr2 >>, |
364 | C<-1> on error. On success, null-terminated names can be found as C<< req->ptr2 >>, |
344 | and C<struct eio_dirents>, if requested by C<flags>, can be found via C<< |
365 | and C<struct eio_dirents>, if requested by C<flags>, can be found via C<< |
345 | req->ptr1 >>. |
366 | req->ptr1 >>. |
346 | |
367 | |
347 | Here is an example that prints all the names: |
368 | Here is an example that prints all the names: |
348 | |
369 | |
… | |
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480 | =item eio_sync_file_range (int fd, off_t offset, size_t nbytes, unsigned int flags, int pri, eio_cb cb, void *data) |
501 | =item eio_sync_file_range (int fd, off_t offset, size_t nbytes, unsigned int flags, int pri, eio_cb cb, void *data) |
481 | |
502 | |
482 | Calls C<sync_file_range>. If the syscall is missing, then this is the same |
503 | Calls C<sync_file_range>. If the syscall is missing, then this is the same |
483 | as calling C<fdatasync>. |
504 | as calling C<fdatasync>. |
484 | |
505 | |
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506 | Flags can be any combination of C<EIO_SYNC_FILE_RANGE_WAIT_BEFORE>, |
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507 | C<EIO_SYNC_FILE_RANGE_WRITE> and C<EIO_SYNC_FILE_RANGE_WAIT_AFTER>. |
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508 | |
485 | =back |
509 | =back |
486 | |
510 | |
487 | =head3 LIBEIO-SPECIFIC REQUESTS |
511 | =head3 LIBEIO-SPECIFIC REQUESTS |
488 | |
512 | |
489 | These requests are specific to libeio and do not correspond to any OS call. |
513 | These requests are specific to libeio and do not correspond to any OS call. |
490 | |
514 | |
491 | =over 4 |
515 | =over 4 |
492 | |
516 | |
493 | =item eio_mtouch (void *addr, size_t length, int flags, int pri, eio_cb cb, void *data) |
517 | =item eio_mtouch (void *addr, size_t length, int flags, int pri, eio_cb cb, void *data) |
494 | |
518 | |
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519 | Reads (C<flags == 0>) or modifies (C<flags == EIO_MT_MODIFY) the given |
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520 | memory area, page-wise, that is, it reads (or reads and writes back) the |
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521 | first octet of every page that spans the memory area. |
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522 | |
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523 | This can be used to page in some mmapped file, or dirty some pages. Note |
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524 | that dirtying is an unlocked read-write access, so races can ensue when |
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525 | the some other thread modifies the data stored in that memory area. |
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526 | |
495 | =item eio_custom (void (*)(eio_req *) execute, int pri, eio_cb cb, void *data) |
527 | =item eio_custom (void (*)(eio_req *) execute, int pri, eio_cb cb, void *data) |
496 | |
528 | |
497 | Executes a custom request, i.e., a user-specified callback. |
529 | Executes a custom request, i.e., a user-specified callback. |
498 | |
530 | |
499 | The callback gets the C<eio_req *> as parameter and is expected to read |
531 | The callback gets the C<eio_req *> as parameter and is expected to read |
500 | and modify any request-specific members. Specifically, it should set C<< |
532 | and modify any request-specific members. Specifically, it should set C<< |
… | |
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520 | req->result = open (req->data, O_RDONLY); |
552 | req->result = open (req->data, O_RDONLY); |
521 | } |
553 | } |
522 | |
554 | |
523 | eio_custom (my_open, 0, my_open_done, "/etc/passwd"); |
555 | eio_custom (my_open, 0, my_open_done, "/etc/passwd"); |
524 | |
556 | |
525 | =item eio_busy (eio_tstamp delay, int pri, eio_cb cb, void *data) |
557 | =item eio_busy (eio_tstamp delay, int pri, eio_cb cb, void *data) |
526 | |
558 | |
527 | This is a a request that takes C<delay> seconds to execute, but otherwise |
559 | This is a a request that takes C<delay> seconds to execute, but otherwise |
528 | does nothing - it simply puts one of the worker threads to sleep for this |
560 | does nothing - it simply puts one of the worker threads to sleep for this |
529 | long. |
561 | long. |
530 | |
562 | |
531 | This request can be used to artificially increase load, e.g. for debugging |
563 | This request can be used to artificially increase load, e.g. for debugging |
532 | or benchmarking reasons. |
564 | or benchmarking reasons. |
533 | |
565 | |
534 | =item eio_nop (int pri, eio_cb cb, void *data) |
566 | =item eio_nop (int pri, eio_cb cb, void *data) |
535 | |
567 | |
536 | This request does nothing, except go through the whole request cycle. This |
568 | This request does nothing, except go through the whole request cycle. This |
537 | can be used to measure latency or in some cases to simplify code, but is |
569 | can be used to measure latency or in some cases to simplify code, but is |
538 | not really of much use. |
570 | not really of much use. |
539 | |
571 | |
540 | =back |
572 | =back |
541 | |
573 | |
542 | =head3 GROUPING AND LIMITING REQUESTS |
574 | =head3 GROUPING AND LIMITING REQUESTS |
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575 | |
|
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576 | There is one more rather special request, C<eio_grp>. It is a very special |
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577 | aio request: Instead of doing something, it is a container for other eio |
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578 | requests. |
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579 | |
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580 | There are two primary use cases for this: a) bundle many requests into a |
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581 | single, composite, request with a definite callback and the ability to |
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582 | cancel the whole request with its subrequests and b) limiting the number |
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583 | of "active" requests. |
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584 | |
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585 | Further below you will find more dicussion of these topics - first follows |
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586 | the reference section detailing the request generator and other methods. |
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587 | |
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588 | =over 4 |
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589 | |
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590 | =item eio_grp (eio_cb cb, void *data) |
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591 | |
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592 | Creates and submits a group request. |
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593 | |
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594 | =back |
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595 | |
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596 | |
543 | |
597 | |
544 | #TODO |
598 | #TODO |
545 | |
599 | |
546 | /*****************************************************************************/ |
600 | /*****************************************************************************/ |
547 | /* groups */ |
601 | /* groups */ |