[arrow] branch main updated: GH-35617: [Docs] Current n_buffers use in C API example (#35626)

[ko...@apache.org]

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The following commit(s) were added to refs/heads/main by this push:
     new aaf6259174 GH-35617: [Docs] Current n_buffers use in C API example (#35626)
aaf6259174 is described below

commit aaf62591741a2f3b4df0d84273ebdbdcb01a8005
Author: Dirk Eddelbuettel <ed...@debian.org>
AuthorDate: Tue May 16 18:53:31 2023 -0500

    GH-35617: [Docs] Current n_buffers use in C API example (#35626)
    
    ### Rationale for this change
    
    As described in #35617 the example in docs suffers from a likely copy-and-paste error as the `n_buffers` value references the _parent_ rather that the two children where this is used. `g++-12` spots this and bemoans that assigning to, respectively, `buffers[1]` and then `buffers[1]` and `buffers[2]` is out of bounds.
    
    ### What changes are included in this PR?
    
    The example is corrected.
    
    ### Are these changes tested?
    
    Yes, locally.  The warnings under `g++-12` go away.
    
    ### Are there any user-facing changes?
    
    Not in behavior but the documentation is improved.
    
    * Closes: #35617
    
    Authored-by: Dirk Eddelbuettel <ed...@debian.org>
    Signed-off-by: Sutou Kouhei <ko...@clear-code.com>
---
 docs/source/format/CDataInterface.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/source/format/CDataInterface.rst b/docs/source/format/CDataInterface.rst
index 17a5e37cd7..fde872ff97 100644
--- a/docs/source/format/CDataInterface.rst
+++ b/docs/source/format/CDataInterface.rst
@@ -907,7 +907,7 @@ transferring ownership to the consumer:
          // Bookkeeping
          .release = &release_malloced_array
       };
-      child->buffers = malloc(sizeof(void*) * array->n_buffers);
+      child->buffers = malloc(sizeof(void*) * child->n_buffers);
       child->buffers[0] = float32_nulls;
       child->buffers[1] = float32_data;
 
@@ -927,7 +927,7 @@ transferring ownership to the consumer:
          // Bookkeeping
          .release = &release_malloced_array
       };
-      child->buffers = malloc(sizeof(void*) * array->n_buffers);
+      child->buffers = malloc(sizeof(void*) * child->n_buffers);
       child->buffers[0] = utf8_nulls;
       child->buffers[1] = utf8_offsets;
       child->buffers[2] = utf8_data;