content: rename articles to reinforce convention of short URLs

The Go blog started out on Blogger
(http://web.archive.org/web/20100325005843/http://blog.golang.org/).
Later, we moved to the current self-hosted blog server
with extra Go-specific functionality like playground snippets.

The old Blogger posts have very long URLs that Blogger chose
for us, such as "go-programming-language-turns-two" or
"two-go-talks-lexical-scanning-in-go-and", predating
the convention of giving posts shorter, more share-friendly,
typeable names.

The conversion of the old Blogger posts also predated
the convention of putting supporting files in a subdirectory.

The result is that although we've established new conventions,
you wouldn't know by listing the directory - the old Blogger
content presents a conflicting picture.

This commit renames the posts with very long names
to have shorter, more share-friendly names, and it moves
all supporting files to subdirectories. It also adds a README
documenting the conventions.

For example, blog.golang.org/go-programming-language-turns-two
is now blog.golang.org/2years, matching our more recent birthday
post URLs, and its supporting files are moved to the new 2years/ directory.

The old URLs redirect to the new ones.

Change-Id: I9f46a790c2c8fab8459aeda73d4e3d2efc86d88f
Reviewed-on: https://go-review.googlesource.com/c/blog/+/223599
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Andrew Bonventre <andybons@golang.org>

1 files changed, 0 insertions, 150 deletions

diff --git a/content/c-go-cgo.article b/content/c-go-cgo.article
deleted file mode 100644
index b344def..0000000
--- a/content/c-go-cgo.article
+++ /dev/null
@@ -1,150 +0,0 @@
-# C? Go? Cgo!
-17 Mar 2011
-Tags: cgo, technical
-Summary: How to use cgo to let Go packages call C code.
-
-Andrew Gerrand
-
-## Introduction
-
-Cgo lets Go packages call C code. Given a Go source file written with some special features,
-cgo outputs Go and C files that can be combined into a single Go package.
-
-To lead with an example, here's a Go package that provides two functions -
-`Random` and `Seed` - that wrap C's `random` and `srandom` functions.
-
-	package rand
-
-	/*
-	#include <stdlib.h>
-	*/
-	import "C"
-
-	func Random() int {
-	    return int(C.random())
-	}
-
-	func Seed(i int) {
-	    C.srandom(C.uint(i))
-	}
-
-Let's look at what's happening here, starting with the import statement.
-
-The `rand` package imports `"C"`, but you'll find there's no such package
-in the standard Go library.
-That's because `C` is a "pseudo-package",
-a special name interpreted by cgo as a reference to C's name space.
-
-The `rand` package contains four references to the `C` package:
-the calls to `C.random` and `C.srandom`, the conversion `C.uint(i)`,
-and the `import` statement.
-
-The `Random` function calls the standard C library's `random` function and returns the result.
-In C, `random` returns a value of the C type `long`,
-which cgo represents as the type `C.long`.
-It must be converted to a Go type before it can be used by Go code outside this package,
-using an ordinary Go type conversion:
-
-	func Random() int {
-	    return int(C.random())
-	}
-
-Here's an equivalent function that uses a temporary variable to illustrate the type conversion more explicitly:
-
-	func Random() int {
-	    var r C.long = C.random()
-	    return int(r)
-	}
-
-The `Seed` function does the reverse, in a way.
-It takes a regular Go `int`, converts it to the C `unsigned int` type,
-and passes it to the C function `srandom`.
-
-	func Seed(i int) {
-	    C.srandom(C.uint(i))
-	}
-
-Note that cgo knows the `unsigned int` type as `C.uint`;
-see the [cgo documentation](https://golang.org/cmd/cgo) for a complete
-list of these numeric type names.
-
-The one detail of this example we haven't examined yet is the comment above the `import` statement.
-
-	/*
-	#include <stdlib.h>
-	*/
-	import "C"
-
-Cgo recognizes this comment.  Any lines starting with `#cgo` followed by
-a space character are removed;
-these become directives for cgo.
-The remaining lines are used as a header when compiling the C parts of the package.
-In this case those lines are just a single `#include` statement,
-but they can be almost any C code.
-The `#cgo` directives are used to provide flags for the compiler and linker
-when building the C parts of the package.
-
-There is a limitation: if your program uses any `//export` directives,
-then the C code in the comment may only include declarations (`extern int f();`),
-not definitions (`int f() { return 1; }`).
-You can use `//export` directives to make Go functions accessible to C code.
-
-The `#cgo` and `//export` directives are documented in the [cgo documentation](https://golang.org/cmd/cgo/).
-
-## Strings and things
-
-Unlike Go, C doesn't have an explicit string type. Strings in C are represented by a zero-terminated array of chars.
-
-Conversion between Go and C strings is done with the `C.CString`,
-`C.GoString`, and `C.GoStringN` functions.
-These conversions make a copy of the string data.
-
-This next example implements a `Print` function that writes a string to
-standard output using C's `fputs` function from the `stdio` library:
-
-	package print
-
-	// #include <stdio.h>
-	// #include <stdlib.h>
-	import "C"
-	import "unsafe"
-
-	func Print(s string) {
-	    cs := C.CString(s)
-	    C.fputs(cs, (*C.FILE)(C.stdout))
-	    C.free(unsafe.Pointer(cs))
-	}
-
-Memory allocations made by C code are not known to Go's memory manager.
-When you create a C string with `C.CString` (or any C memory allocation)
-you must remember to free the memory when you're done with it by calling `C.free`.
-
-The call to `C.CString` returns a pointer to the start of the char array,
-so before the function exits we convert it to an [`unsafe.Pointer`](https://golang.org/pkg/unsafe/#Pointer)
-and release the memory allocation with `C.free`.
-A common idiom in cgo programs is to [`defer`](https://golang.org/doc/articles/defer_panic_recover.html)
-the free immediately after allocating (especially when the code that follows
-is more complex than a single function call),
-as in this rewrite of `Print`:
-
-	func Print(s string) {
-	    cs := C.CString(s)
-	    defer C.free(unsafe.Pointer(cs))
-	    C.fputs(cs, (*C.FILE)(C.stdout))
-	}
-
-## Building cgo packages
-
-To build cgo packages, just use [`go build`](https://golang.org/cmd/go/#Compile_packages_and_dependencies)
-or [`go install`](https://golang.org/cmd/go/#Compile_and_install_packages_and_dependencies) as usual.
-The go tool recognizes the special `"C"` import and automatically uses cgo for those files.
-
-## More cgo resources
-
-The [cgo command](https://golang.org/cmd/cgo/) documentation has more
-detail about the C pseudo-package and the build process.
-The [cgo examples](https://golang.org/misc/cgo/) in the Go tree demonstrate
-more advanced concepts.
-
-Finally, if you're curious as to how all this works internally,
-take a look at the introductory comment of the runtime package's [cgocall.go](https://golang.org/src/runtime/cgocall.go).