Current File : //usr/share/doc/sg3-utils/examples/archive/align_b4_memalign.c
/* Code fragment of how to get a buffer from the heap that has a specific
* alignment. The typical alignment is to a "page" whose size is often
* 4096 bytes. */
uint8_t * wrkBuff; /* will get pointer to heap allocation */
uint8_t * wrkPos; /* will get aligned pointer within wrkBuff */
uint32_t sz_of_aligned = 1234; /* number of aligned bytes required */
int psz;
#if defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
psz = sysconf(_SC_PAGESIZE); /* POSIX.1 (was getpagesize()) */
#else
psz = 4096; /* give up, pick likely figure */
#endif
/* perhaps use posix_memalign() instead. Yes but not always available */
wrkBuff = (uint8_t *)malloc(sz_of_aligned + psz);
wrkPos = (uint8_t *)(((sg_uintptr_t)wrkBuff + psz - 1) & (~(psz - 1)));
/* The disadvantage of this approach is that it needs both wrkBuff and wrkPos
* to be held by the application. The wrkBuff is only needed for the
* corresponding free(), all other uses should be via wrkPos. */
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