diff options
Diffstat (limited to 'man3/posix_memalign.3')
| -rw-r--r-- | man3/posix_memalign.3 | 276 |
1 files changed, 0 insertions, 276 deletions
diff --git a/man3/posix_memalign.3 b/man3/posix_memalign.3 deleted file mode 100644 index 194c55a..0000000 --- a/man3/posix_memalign.3 +++ /dev/null @@ -1,276 +0,0 @@ -'\" t -.\" Copyright (c) 2001 by John Levon <moz@compsoc.man.ac.uk> -.\" Based in part on GNU libc documentation. -.\" -.\" SPDX-License-Identifier: Linux-man-pages-copyleft -.\" -.\" 2001-10-11, 2003-08-22, aeb, added some details -.\" 2012-03-23, Michael Kerrisk <mtk.manpages@mail.com> -.\" Document pvalloc() and aligned_alloc() -.TH posix_memalign 3 2023-11-24 "Linux man-pages 6.7" -.SH NAME -posix_memalign, aligned_alloc, memalign, valloc, pvalloc \- -allocate aligned memory -.SH LIBRARY -Standard C library -.RI ( libc ", " \-lc ) -.SH SYNOPSIS -.nf -.B #include <stdlib.h> -.P -.BI "int posix_memalign(void **" memptr ", size_t " alignment ", size_t " size ); -.BI "void *aligned_alloc(size_t " alignment ", size_t " size ); -.BI "[[deprecated]] void *valloc(size_t " size ); -.P -.B #include <malloc.h> -.P -.BI "[[deprecated]] void *memalign(size_t " alignment ", size_t " size ); -.BI "[[deprecated]] void *pvalloc(size_t " size ); -.fi -.P -.RS -4 -Feature Test Macro Requirements for glibc (see -.BR feature_test_macros (7)): -.RE -.P -.BR posix_memalign (): -.nf - _POSIX_C_SOURCE >= 200112L -.fi -.P -.BR aligned_alloc (): -.nf - _ISOC11_SOURCE -.fi -.P -.BR valloc (): -.nf - Since glibc 2.12: - (_XOPEN_SOURCE >= 500) && !(_POSIX_C_SOURCE >= 200112L) - || /* glibc >= 2.19: */ _DEFAULT_SOURCE - || /* glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE - Before glibc 2.12: - _BSD_SOURCE || _XOPEN_SOURCE >= 500 -.\" || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED -.fi -.SH DESCRIPTION -.BR posix_memalign () -allocates -.I size -bytes and places the address of the allocated memory in -.IR "*memptr" . -The address of the allocated memory will be a multiple of -.IR "alignment" , -which must be a power of two and a multiple of -.IR "sizeof(void\ *)" . -This address can later be successfully passed to -.BR free (3). -If -.I size -is 0, then -the value placed in -.I *memptr -is either NULL -.\" glibc does this: -or a unique pointer value. -.P -The obsolete function -.BR memalign () -allocates -.I size -bytes and returns a pointer to the allocated memory. -The memory address will be a multiple of -.IR alignment , -which must be a power of two. -.\" The behavior of memalign() for size==0 is as for posix_memalign() -.\" but no standards govern this. -.P -.BR aligned_alloc () -is the same as -.BR memalign (), -except for the added restriction that -.I alignment -must be a power of two. -.P -The obsolete function -.BR valloc () -allocates -.I size -bytes and returns a pointer to the allocated memory. -The memory address will be a multiple of the page size. -It is equivalent to -.IR "memalign(sysconf(_SC_PAGESIZE),size)" . -.P -The obsolete function -.BR pvalloc () -is similar to -.BR valloc (), -but rounds the size of the allocation up to -the next multiple of the system page size. -.P -For all of these functions, the memory is not zeroed. -.SH RETURN VALUE -.BR aligned_alloc (), -.BR memalign (), -.BR valloc (), -and -.BR pvalloc () -return a pointer to the allocated memory on success. -On error, NULL is returned, and \fIerrno\fP is set -to indicate the error. -.P -.BR posix_memalign () -returns zero on success, or one of the error values listed in the -next section on failure. -The value of -.I errno -is not set. -On Linux (and other systems), -.BR posix_memalign () -does not modify -.I memptr -on failure. -A requirement standardizing this behavior was added in POSIX.1-2008 TC2. -.\" http://austingroupbugs.net/view.php?id=520 -.SH ERRORS -.TP -.B EINVAL -The -.I alignment -argument was not a power of two, or was not a multiple of -.IR "sizeof(void\ *)" . -.TP -.B ENOMEM -Out of memory. -.SH ATTRIBUTES -For an explanation of the terms used in this section, see -.BR attributes (7). -.TS -allbox; -lbx lb lb -l l l. -Interface Attribute Value -T{ -.na -.nh -.BR aligned_alloc (), -.BR memalign (), -.BR posix_memalign () -T} Thread safety MT-Safe -T{ -.na -.nh -.BR valloc (), -.BR pvalloc () -T} Thread safety MT-Unsafe init -.TE -.SH STANDARDS -.TP -.BR aligned_alloc () -C11. -.TP -.BR posix_memalign () -POSIX.1-2008. -.TP -.BR memalign () -.TQ -.BR valloc () -None. -.TP -.BR pvalloc () -GNU. -.SH HISTORY -.TP -.BR aligned_alloc () -glibc 2.16. -C11. -.TP -.BR posix_memalign () -glibc 2.1.91. -POSIX.1d, POSIX.1-2001. -.TP -.BR memalign () -glibc 2.0. -SunOS 4.1.3. -.TP -.BR valloc () -glibc 2.0. -3.0BSD. -Documented as obsolete in 4.3BSD, -and as legacy in SUSv2. -.TP -.BR pvalloc () -glibc 2.0. -.\" -.SS Headers -Everybody agrees that -.BR posix_memalign () -is declared in \fI<stdlib.h>\fP. -.P -On some systems -.BR memalign () -is declared in \fI<stdlib.h>\fP instead of \fI<malloc.h>\fP. -.P -According to SUSv2, -.BR valloc () -is declared in \fI<stdlib.h>\fP. -.\" Libc4,5 and -glibc declares it in \fI<malloc.h>\fP, and also in -\fI<stdlib.h>\fP -if suitable feature test macros are defined (see above). -.SH NOTES -On many systems there are alignment restrictions, for example, on buffers -used for direct block device I/O. -POSIX specifies the -.I "pathconf(path,_PC_REC_XFER_ALIGN)" -call that tells what alignment is needed. -Now one can use -.BR posix_memalign () -to satisfy this requirement. -.P -.BR posix_memalign () -verifies that -.I alignment -matches the requirements detailed above. -.BR memalign () -may not check that the -.I alignment -argument is correct. -.P -POSIX requires that memory obtained from -.BR posix_memalign () -can be freed using -.BR free (3). -Some systems provide no way to reclaim memory allocated with -.BR memalign () -or -.BR valloc () -(because one can pass to -.BR free (3) -only a pointer obtained from -.BR malloc (3), -while, for example, -.BR memalign () -would call -.BR malloc (3) -and then align the obtained value). -.\" Other systems allow passing the result of -.\" .IR valloc () -.\" to -.\" .IR free (3), -.\" but not to -.\" .IR realloc (3). -The glibc implementation -allows memory obtained from any of these functions to be -reclaimed with -.BR free (3). -.P -The glibc -.BR malloc (3) -always returns 8-byte aligned memory addresses, so these functions are -needed only if you require larger alignment values. -.SH SEE ALSO -.BR brk (2), -.BR getpagesize (2), -.BR free (3), -.BR malloc (3) |