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| 236 | } |
236 | } |
| 237 | |
237 | |
| 238 | In this case, the compiler would probably be smart enough to deduce it on |
238 | In this case, the compiler would probably be smart enough to deduce it on |
| 239 | its own, so this is mainly useful for declarations. |
239 | its own, so this is mainly useful for declarations. |
| 240 | |
240 | |
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241 | =item ecb_restrict |
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242 | |
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243 | Expands to the C<restrict> keyword or equivalent on compilers that support |
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244 | them, and to nothing on others. Must be specified on a pointer type or |
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245 | an array index to indicate that the memory doesn't alias with any other |
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246 | restricted pointer in the same scope. |
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247 | |
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248 | Example: multiply a vector, and allow the compiler to parallelise the |
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249 | loop, because it knows it doesn't overwrite input values. |
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250 | |
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251 | void |
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252 | multiply (float *ecb_restrict src, |
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253 | float *ecb_restrict dst, |
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254 | int len, float factor) |
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255 | { |
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256 | int i; |
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257 | |
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258 | for (i = 0; i < len; ++i) |
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259 | dst [i] = src [i] * factor; |
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260 | } |
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261 | |
| 241 | =item ecb_const |
262 | =item ecb_const |
| 242 | |
263 | |
| 243 | Declares that the function only depends on the values of its arguments, |
264 | Declares that the function only depends on the values of its arguments, |
| 244 | much like a mathematical function. It specifically does not read or write |
265 | much like a mathematical function. It specifically does not read or write |
| 245 | any memory any arguments might point to, global variables, or call any |
266 | any memory any arguments might point to, global variables, or call any |
