Add the posix_memalign(3) function to bionic
The posix_memalign(3) function is very similar to the traditional
memalign(3) function, but with better error reporting and a guarantee
that the memory it allocates can be freed. In bionic, memalign(3)
allocated memory can be freed, so posix_memalign(3) is just a wrapper
around memalign(3).
Change-Id: I62ee908aa5ba6b887d8446a00d8298d080a6a299
diff --git a/libc/bionic/dlmalloc.c b/libc/bionic/dlmalloc.c
index 8c75e9c..496cd1c 100644
--- a/libc/bionic/dlmalloc.c
+++ b/libc/bionic/dlmalloc.c
@@ -774,6 +774,22 @@
void* dlmemalign(size_t, size_t);
/*
+ int posix_memalign(void **memptr, size_t alignment, size_t size);
+ Places a pointer to a newly allocated chunk of size bytes, aligned
+ in accord with the alignment argument, in *memptr.
+
+ The return value is 0 on success, and ENOMEM on failure.
+
+ The alignment argument should be a power of two. If the argument is
+ not a power of two, the nearest greater power is used.
+ 8-byte alignment is guaranteed by normal malloc calls, so don't
+ bother calling memalign with an argument of 8 or less.
+
+ Overreliance on posix_memalign is a sure way to fragment space.
+*/
+int posix_memalign(void **memptr, size_t alignment, size_t size);
+
+/*
valloc(size_t n);
Equivalent to memalign(pagesize, n), where pagesize is the page
size of the system. If the pagesize is unknown, 4096 is used.
@@ -4507,6 +4523,18 @@
return internal_memalign(gm, alignment, bytes);
}
+int posix_memalign(void **memptr, size_t alignment, size_t size) {
+ int ret = 0;
+
+ *memptr = dlmemalign(alignment, size);
+
+ if (*memptr == 0) {
+ ret = ENOMEM;
+ }
+
+ return ret;
+}
+
void** dlindependent_calloc(size_t n_elements, size_t elem_size,
void* chunks[]) {
size_t sz = elem_size; /* serves as 1-element array */
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index 5dc8a87..e5caadd 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -67,6 +67,8 @@
extern unsigned long long strtoull(const char *, char **, int);
extern double strtod(const char *nptr, char **endptr);
+extern int posix_memalign(void **memptr, size_t alignment, size_t size);
+
static __inline__ float strtof(const char *nptr, char **endptr)
{
return (float)strtod(nptr, endptr);