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| Next: <a href="Filesystem.html#Filesystem" accesskey="n" rel="next">Filesystem</a>, Up: <a href="Host-Config.html#Host-Config" accesskey="u" rel="up">Host Config</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p> |
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| <a name="Host-Common-1"></a> |
| <h3 class="section">18.1 Host Common</h3> |
| <a name="index-host-hooks"></a> |
| <a name="index-host-functions"></a> |
| |
| <p>Some things are just not portable, even between similar operating systems, |
| and are too difficult for autoconf to detect. They get implemented using |
| hook functions in the file specified by the <var>host_hook_obj</var> |
| variable in <samp>config.gcc</samp>. |
| </p> |
| <dl> |
| <dt><a name="index-HOST_005fHOOKS_005fEXTRA_005fSIGNALS"></a>Host Hook: <em>void</em> <strong>HOST_HOOKS_EXTRA_SIGNALS</strong> <em>(void)</em></dt> |
| <dd><p>This host hook is used to set up handling for extra signals. The most |
| common thing to do in this hook is to detect stack overflow. |
| </p></dd></dl> |
| |
| <dl> |
| <dt><a name="index-HOST_005fHOOKS_005fGT_005fPCH_005fGET_005fADDRESS"></a>Host Hook: <em>void *</em> <strong>HOST_HOOKS_GT_PCH_GET_ADDRESS</strong> <em>(size_t <var>size</var>, int <var>fd</var>)</em></dt> |
| <dd><p>This host hook returns the address of some space that is likely to be |
| free in some subsequent invocation of the compiler. We intend to load |
| the PCH data at this address such that the data need not be relocated. |
| The area should be able to hold <var>size</var> bytes. If the host uses |
| <code>mmap</code>, <var>fd</var> is an open file descriptor that can be used for |
| probing. |
| </p></dd></dl> |
| |
| <dl> |
| <dt><a name="index-HOST_005fHOOKS_005fGT_005fPCH_005fUSE_005fADDRESS"></a>Host Hook: <em>int</em> <strong>HOST_HOOKS_GT_PCH_USE_ADDRESS</strong> <em>(void * <var>address</var>, size_t <var>size</var>, int <var>fd</var>, size_t <var>offset</var>)</em></dt> |
| <dd><p>This host hook is called when a PCH file is about to be loaded. |
| We want to load <var>size</var> bytes from <var>fd</var> at <var>offset</var> |
| into memory at <var>address</var>. The given address will be the result of |
| a previous invocation of <code>HOST_HOOKS_GT_PCH_GET_ADDRESS</code>. |
| Return -1 if we couldn’t allocate <var>size</var> bytes at <var>address</var>. |
| Return 0 if the memory is allocated but the data is not loaded. Return 1 |
| if the hook has performed everything. |
| </p> |
| <p>If the implementation uses reserved address space, free any reserved |
| space beyond <var>size</var>, regardless of the return value. If no PCH will |
| be loaded, this hook may be called with <var>size</var> zero, in which case |
| all reserved address space should be freed. |
| </p> |
| <p>Do not try to handle values of <var>address</var> that could not have been |
| returned by this executable; just return -1. Such values usually |
| indicate an out-of-date PCH file (built by some other GCC executable), |
| and such a PCH file won’t work. |
| </p></dd></dl> |
| |
| <dl> |
| <dt><a name="index-HOST_005fHOOKS_005fGT_005fPCH_005fALLOC_005fGRANULARITY"></a>Host Hook: <em>size_t</em> <strong>HOST_HOOKS_GT_PCH_ALLOC_GRANULARITY</strong> <em>(void);</em></dt> |
| <dd><p>This host hook returns the alignment required for allocating virtual |
| memory. Usually this is the same as getpagesize, but on some hosts the |
| alignment for reserving memory differs from the pagesize for committing |
| memory. |
| </p></dd></dl> |
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