Author: Matti Picus <matti.pi...@gmail.com>
Branch: doc-set_source
Changeset: r3053:889d38233ce8
Date: 2017-12-29 09:30 +0200
http://bitbucket.org/cffi/cffi/changeset/889d38233ce8/
Log: try to clarify set_source() requires str(<code that implements
functions>)
diff --git a/doc/source/overview.rst b/doc/source/overview.rst
--- a/doc/source/overview.rst
+++ b/doc/source/overview.rst
@@ -76,20 +76,25 @@
ffibuilder = FFI()
ffibuilder.set_source("_example",
- r""" // passed to the real C compiler
+ r""" // passed to the real C compiler,
+ // contains implementation of things declared in cdef()
#include <sys/types.h>
#include <pwd.h>
+ struct passwd *mygetpwuid(int uid) {
+ return getpwuid(uid);
+ }
""",
libraries=[]) # or a list of libraries to link with
# (more arguments like setup.py's Extension class:
# include_dirs=[..], extra_objects=[..], and so on)
- ffibuilder.cdef(""" // some declarations from the man page
+ ffibuilder.cdef("""
+ // declarations that are shared between python and C
struct passwd {
char *pw_name;
...; // literally dot-dot-dot
};
- struct passwd *getpwuid(int uid);
+ struct passwd *mygetpwuid(int uid);
""")
if __name__ == "__main__":
@@ -111,14 +116,14 @@
from _example import ffi, lib
- p = lib.getpwuid(0)
+ p = lib.mygetpwuid(0)
assert ffi.string(p.pw_name) == b'root'
Note that this works independently of the exact C layout of ``struct
passwd`` (it is "API level", as opposed to "ABI level"). It requires
a C compiler in order to run ``example_build.py``, but it is much more
portable than trying to get the details of the fields of ``struct
-passwd`` exactly right. Similarly, we declared ``getpwuid()`` as
+passwd`` exactly right. Similarly, we declared ``mygetpwuid()`` as
taking an ``int`` argument. On some platforms this might be slightly
incorrect---but it does not matter. It is also faster than the ABI
mode.
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