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| <h3 class="section">12.2 Reentrant covers for OS subroutines</h3> |
| |
| <p>Since the system subroutines are used by other library routines that |
| require reentrancy, <samp><span class="file">libc.a</span></samp> provides cover routines (for example, |
| the reentrant version of <code>fork</code> is <code>_fork_r</code>). These cover |
| routines are consistent with the other reentrant subroutines in this |
| library, and achieve reentrancy by using a reserved global data block |
| (see <a href="Reentrancy.html#Reentrancy">Reentrancy</a>). |
| |
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| <dl> |
| <dt><code>_open_r</code><a name="index-g_t_005fopen_005fr-485"></a><dd>A reentrant version of <code>open</code>. It takes a pointer |
| to the global data block, which holds <code>errno</code>. |
| |
| <pre class="example"> int _open_r(void *<var>reent</var>, |
| const char *<var>file</var>, int <var>flags</var>, int <var>mode</var>); |
| </pre> |
| <br><dt><code>_close_r</code><a name="index-g_t_005fclose_005fr-486"></a><dd>A reentrant version of <code>close</code>. It takes a pointer to the global |
| data block, which holds <code>errno</code>. |
| |
| <pre class="example"> int _close_r(void *<var>reent</var>, int <var>fd</var>); |
| </pre> |
| <br><dt><code>_lseek_r</code><a name="index-g_t_005flseek_005fr-487"></a><dd>A reentrant version of <code>lseek</code>. It takes a pointer to the global |
| data block, which holds <code>errno</code>. |
| |
| <pre class="example"> off_t _lseek_r(void *<var>reent</var>, |
| int <var>fd</var>, off_t <var>pos</var>, int <var>whence</var>); |
| </pre> |
| <br><dt><code>_read_r</code><a name="index-g_t_005fread_005fr-488"></a><dd>A reentrant version of <code>read</code>. It takes a pointer to the global |
| data block, which holds <code>errno</code>. |
| |
| <pre class="example"> long _read_r(void *<var>reent</var>, |
| int <var>fd</var>, void *<var>buf</var>, size_t <var>cnt</var>); |
| </pre> |
| <br><dt><code>_write_r</code><a name="index-g_t_005fwrite_005fr-489"></a><dd>A reentrant version of <code>write</code>. It takes a pointer to the global |
| data block, which holds <code>errno</code>. |
| |
| <pre class="example"> long _write_r(void *<var>reent</var>, |
| int <var>fd</var>, const void *<var>buf</var>, size_t <var>cnt</var>); |
| </pre> |
| <br><dt><code>_fork_r</code><a name="index-g_t_005ffork_005fr-490"></a><dd>A reentrant version of <code>fork</code>. It takes a pointer to the global |
| data block, which holds <code>errno</code>. |
| |
| <pre class="example"> int _fork_r(void *<var>reent</var>); |
| </pre> |
| <br><dt><code>_wait_r</code><a name="index-g_t_005fwait_005fr-491"></a><dd>A reentrant version of <code>wait</code>. It takes a pointer to the global |
| data block, which holds <code>errno</code>. |
| |
| <pre class="example"> int _wait_r(void *<var>reent</var>, int *<var>status</var>); |
| </pre> |
| <br><dt><code>_stat_r</code><a name="index-g_t_005fstat_005fr-492"></a><dd>A reentrant version of <code>stat</code>. It takes a pointer to the global |
| data block, which holds <code>errno</code>. |
| |
| <pre class="example"> int _stat_r(void *<var>reent</var>, |
| const char *<var>file</var>, struct stat *<var>pstat</var>); |
| </pre> |
| <br><dt><code>_fstat_r</code><a name="index-g_t_005ffstat_005fr-493"></a><dd>A reentrant version of <code>fstat</code>. It takes a pointer to the global |
| data block, which holds <code>errno</code>. |
| |
| <pre class="example"> int _fstat_r(void *<var>reent</var>, |
| int <var>fd</var>, struct stat *<var>pstat</var>); |
| </pre> |
| <br><dt><code>_link_r</code><a name="index-g_t_005flink_005fr-494"></a><dd>A reentrant version of <code>link</code>. It takes a pointer to the global |
| data block, which holds <code>errno</code>. |
| |
| <pre class="example"> int _link_r(void *<var>reent</var>, |
| const char *<var>old</var>, const char *<var>new</var>); |
| </pre> |
| <br><dt><code>_unlink_r</code><a name="index-g_t_005funlink_005fr-495"></a><dd>A reentrant version of <code>unlink</code>. It takes a pointer to the global |
| data block, which holds <code>errno</code>. |
| |
| <pre class="example"> int _unlink_r(void *<var>reent</var>, const char *<var>file</var>); |
| </pre> |
| <br><dt><code>_sbrk_r</code><a name="index-g_t_005fsbrk_005fr-496"></a><dd>A reentrant version of <code>sbrk</code>. It takes a pointer to the global |
| data block, which holds <code>errno</code>. |
| |
| <pre class="example"> char *_sbrk_r(void *<var>reent</var>, size_t <var>incr</var>); |
| </pre> |
| </dl> |
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