DOC: Fix code example in c-info.python-as-glue.rst.

Corrections to #8023.

- Fix index types to ssize_t.
- Clean up C code style.

Closes #7701.

[ci skip]

1 files changed, 21 insertions, 16 deletions

diff --git a/doc/source/user/c-info.python-as-glue.rst b/doc/source/user/c-info.python-as-glue.rst
index cc360e966..84248def1 100644
--- a/doc/source/user/c-info.python-as-glue.rst
+++ b/doc/source/user/c-info.python-as-glue.rst
@@ -902,27 +902,32 @@ The ``code.c`` file also contains the function ``dfilter2d``:
 
 .. code-block:: c
 
-    /* Assumes b is contiguous and
-       a has strides that are multiples of sizeof(double)
-    */
+    /*
+     * Assumes b is contiguous and has strides that are multiples of
+     * sizeof(double)
+     */
     void
-    dfilter2d(double *a, double *b, int *astrides, int *dims)
+    dfilter2d(double *a, double *b, ssize_t *astrides, ssize_t *dims)
     {
-        int i, j, M, N, S0, S1;
-        int r, c, rm1, rp1, cp1, cm1;
+        ssize_t i, j, M, N, S0, S1;
+        ssize_t r, c, rm1, rp1, cp1, cm1;
 
         M = dims[0]; N = dims[1];
         S0 = astrides[0]/sizeof(double);
-        S1=astrides[1]/sizeof(double);
-        for (i=1; i<M-1; i++) {
-            r = i*S0; rp1 = r+S0; rm1 = r-S0;
-            for (j=1; j<N-1; j++) {
-                c = j*S1; cp1 = j+S1; cm1 = j-S1;
-                b[i*N+j] = a[r+c] +                 \
-                    (a[rp1+c] + a[rm1+c] +          \
-                     a[r+cp1] + a[r+cm1])*0.5 +     \
-                    (a[rp1+cp1] + a[rp1+cm1] +      \
-                     a[rm1+cp1] + a[rm1+cp1])*0.25;
+        S1 = astrides[1]/sizeof(double);
+        for (i = 1; i < M - 1; i++) {
+            r = i*S0;
+            rp1 = r + S0;
+            rm1 = r - S0;
+            for (j = 1; j < N - 1; j++) {
+                c = j*S1;
+                cp1 = j + S1;
+                cm1 = j - S1;
+                b[i*N + j] = a[r + c] +
+                    (a[rp1 + c] + a[rm1 + c] +
+                     a[r + cp1] + a[r + cm1])*0.5 +
+                    (a[rp1 + cp1] + a[rp1 + cm1] +
+                     a[rm1 + cp1] + a[rm1 + cp1])*0.25;
             }
         }
     }