Move C bindings style guide to C bindings document

1 files changed, 72 insertions, 0 deletions

diff --git a/docs/development/c-bindings.rst b/docs/development/c-bindings.rst
index 910f4d3d..1349af73 100644
--- a/docs/development/c-bindings.rst
+++ b/docs/development/c-bindings.rst
@@ -7,6 +7,78 @@ C bindings are bindings to C libraries, using cffi_ whenever possible.
 
 Bindings live in :py:mod:`cryptography.hazmat.bindings`.
 
+Style guide
+-----------
+
+Don't name parameters:
+
+.. code-block:: c
+
+    /* Good */
+    long f(long);
+    /* Bad */
+    long f(long x);
+
+...unless they're inside a struct:
+
+.. code-block:: c
+
+    struct my_struct {
+        char *name;
+        int number;
+        ...;
+    };
+
+Include ``void`` if the function takes no arguments:
+
+.. code-block:: c
+
+    /* Good */
+    long f(void);
+    /* Bad */
+    long f();
+
+Wrap lines at 80 characters like so:
+
+.. code-block:: c
+
+    /* Pretend this went to 80 characters */
+    long f(long, long,
+           int *)
+
+Include a space after commas between parameters:
+
+.. code-block:: c
+
+    /* Good */
+    long f(int, char *)
+    /* Bad */
+    long f(int,char *)
+
+Use C-style ``/* */`` comments instead of C++-style ``//``:
+
+.. code-block:: c
+
+    // Bad
+    /* Good */
+
+Values set by ``#define`` should be assigned the appropriate type. If you see
+this:
+
+.. code-block:: c
+
+    #define SOME_INTEGER_LITERAL 0x0;
+    #define SOME_UNSIGNED_INTEGER_LITERAL 0x0001U;
+    #define SOME_STRING_LITERAL "hello";
+
+...it should be added to the bindings like so:
+
+.. code-block:: c
+
+    static const int SOME_INTEGER_LITERAL;
+    static const unsigned int SOME_UNSIGNED_INTEGER_LITERAL;
+    static const char *const SOME_STRING_LITERAL;
+
 Adding constant, types, functions...
 ------------------------------------