StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
primarykey
Id
12864850
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
1
CommunityOwnedDate
CreationDate
2012-10-12T18:15:51.810
FavoriteCount
0
LastActivityDate
2012-10-12T18:15:51.810
LastEditDate
LastEditorUserId
0
OwnerUserId
198536
ParentId
12862981
PostTypeId
2
Score
2
ViewCount
0
LastEditorDisplayName
text
Body
In a comment to the question, I wrote that <code>calloc()</code> allows better memory alignment for platforms where it matters. I haven't been able to find anything to support that (yet). I am pretty sure it was a feature of the VMS/VAXC compiler, but source for that is scarce. <hr> However, I did find that <code>calloc()</code> and <code>alloc()</code> appeared at the same time, with the release of Unix V6 in May 1975. In V5, released 11 months earlier, neither function is present; the kernel and runtime library (and assembler and C compiler) were written in assembly. In the V6 release, <a href="http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/source/iolib/calloc.c" rel="nofollow">calloc is implemented</a> as the four line source code module: <pre><code>calloc(n, s) { return(alloc(n*s)); } </code></pre> <code>calloc()</code> does not clear the allocated memory; see <a href="http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/source/iolib/alloc.c" rel="nofollow"><code>alloc()</code></a>, and there was no <code>man</code> page for <code>calloc()</code> in V6; however the <a href="http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/man/man3/alloc.3" rel="nofollow">man page for <code>alloc()</code></a>: <blockquote> DESCRIPTION Alloc and free provide a simple general-purpose core management package. Alloc is given a size in bytes; it returns a pointer to an area at least that size which is even and hence can hold an object of any type. The argument to free is a pointer to an area previously allocated by alloc; this space is made available for further allocation. Needless to say, grave disorder will result if the space assigned by alloc is overrun or if some random number is handed to free. The routine uses a first-fit algorithm which coalesces blocks being freed with other blocks already free. It calls sbrk (see "break (II))" to get more core from the system when there is no suitable space already free. DIAGNOSTICS Returns -1 if there is no available core. BUGS Allocated memory contains garbage instead of being cleared. </blockquote> Not even <code>NULL</code> is returned in the case of memory exhaustion! <code>calloc()</code> first formally appears in UNIX V7, January 1979, along with several other <a href="http://minnie.tuhs.org/cgi-bin/utree.pl?file=V7/usr/man/man3/malloc.3" rel="nofollow">improvements</a>: <ul> <li><code>calloc()</code> clears the memory returned.</li> <li><code>alloc()</code> was renamed to <code>malloc()</code></li> <li><code>realloc()</code> appeared</li> <li>in the case of memory exhaustion or a heap error, the functions "return a null pointer (0)"</li> </ul>
Tags
Title
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. POWhat is the need for having "nmem" and "size" parameters in C functions?
 singulars
 PostTypePostTypeId
 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. This table or related slice is empty.
UserOwnerUserId
1. USwallyk
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. This table or related slice is empty.
VotesPostIdCreationDate
1. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
2. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
CommentsPostId
1. COApologies if I missed something, but how does this answer the question? All I see from the code is that calloc is just a call to alloc but it does the multiplication for you. Is the conclusion that it is just a nicety or that it was just a random implementation detail a developer made up?
 singulars
 PostPostId
 PO
 UserUserId
 USkurtzbot

Querying!

Guidance

A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.