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| |
| <h2 id="introduction">Introduction to Go 1.7</h2> |
| |
| <p> |
| The latest Go release, version 1.7, arrives six months after 1.6. |
| Most of its changes are in the implementation of the toolchain, runtime, and libraries. |
| There is one minor change to the language specification. |
| As always, the release maintains the Go 1 <a href="/doc/go1compat.html">promise of compatibility</a>. |
| We expect almost all Go programs to continue to compile and run as before. |
| </p> |
| |
| <p> |
| The release <a href="#ports">adds a port to IBM LinuxOne</a>; |
| <a href="#compiler">updates the x86-64 compiler back end</a> to generate more efficient code; |
| includes the <a href="#context">context package</a>, promoted from the |
| <a href="https://golang.org/x/net/context">x/net subrepository</a> |
| and now used in the standard library; |
| and <a href="#testing">adds support in the testing package</a> for |
| creating hierarchies of tests and benchmarks. |
| The release also <a href="#cmd_go">finalizes the vendoring support</a> |
| started in Go 1.5, making it a standard feature. |
| </p> |
| |
| <h2 id="language">Changes to the language</h2> |
| |
| <p> |
| There is one tiny language change in this release. |
| The section on <a href="/ref/spec#Terminating_statements">terminating statements</a> |
| clarifies that to determine whether a statement list ends in a terminating statement, |
| the “final non-empty statement” is considered the end, |
| matching the existing behavior of the gc and gccgo compiler toolchains. |
| In earlier releases the definition referred only to the “final statement,” |
| leaving the effect of trailing empty statements at the least unclear. |
| The <a href="/pkg/go/types/"><code>go/types</code></a> |
| package has been updated to match the gc and gccgo compiler toolchains |
| in this respect. |
| This change has no effect on the correctness of existing programs. |
| </p> |
| |
| <h2 id="ports">Ports</h2> |
| |
| <p> |
| Go 1.7 adds support for macOS 10.12 Sierra. |
| Binaries built with versions of Go before 1.7 will not work |
| correctly on Sierra. |
| </p> |
| |
| <p> |
| Go 1.7 adds an experimental port to <a href="https://en.wikipedia.org/wiki/Linux_on_z_Systems">Linux on z Systems</a> (<code>linux/s390x</code>) |
| and the beginning of a port to Plan 9 on ARM (<code>plan9/arm</code>). |
| </p> |
| |
| <p> |
| The experimental ports to Linux on 64-bit MIPS (<code>linux/mips64</code> and <code>linux/mips64le</code>) |
| added in Go 1.6 now have full support for cgo and external linking. |
| </p> |
| |
| <p> |
| The experimental port to Linux on little-endian 64-bit PowerPC (<code>linux/ppc64le</code>) |
| now requires the POWER8 architecture or later. |
| Big-endian 64-bit PowerPC (<code>linux/ppc64</code>) only requires the |
| POWER5 architecture. |
| </p> |
| |
| <p> |
| The OpenBSD port now requires OpenBSD 5.6 or later, for access to the <a href="https://man.openbsd.org/getentropy.2"><i>getentropy</i>(2)</a> system call. |
| </p> |
| |
| <h3 id="known_issues">Known Issues</h3> |
| |
| <p> |
| There are some instabilities on FreeBSD that are known but not understood. |
| These can lead to program crashes in rare cases. |
| See <a href="/issue/16136">issue 16136</a>, |
| <a href="/issue/15658">issue 15658</a>, |
| and <a href="/issue/16396">issue 16396</a>. |
| Any help in solving these FreeBSD-specific issues would be appreciated. |
| </p> |
| |
| <h2 id="tools">Tools</h2> |
| |
| <h3 id="cmd_asm">Assembler</h3> |
| |
| <p> |
| For 64-bit ARM systems, the vector register names have been |
| corrected to <code>V0</code> through <code>V31</code>; |
| previous releases incorrectly referred to them as <code>V32</code> through <code>V63</code>. |
| </p> |
| |
| <p> |
| For 64-bit x86 systems, the following instructions have been added: |
| <code>PCMPESTRI</code>, |
| <code>RORXL</code>, |
| <code>RORXQ</code>, |
| <code>VINSERTI128</code>, |
| <code>VPADDD</code>, |
| <code>VPADDQ</code>, |
| <code>VPALIGNR</code>, |
| <code>VPBLENDD</code>, |
| <code>VPERM2F128</code>, |
| <code>VPERM2I128</code>, |
| <code>VPOR</code>, |
| <code>VPSHUFB</code>, |
| <code>VPSHUFD</code>, |
| <code>VPSLLD</code>, |
| <code>VPSLLDQ</code>, |
| <code>VPSLLQ</code>, |
| <code>VPSRLD</code>, |
| <code>VPSRLDQ</code>, |
| and |
| <code>VPSRLQ</code>. |
| </p> |
| |
| <h3 id="compiler">Compiler Toolchain</h3> |
| |
| <p> |
| This release includes a new code generation back end for 64-bit x86 systems, |
| following a <a href="/s/go17ssa">proposal from 2015</a> |
| that has been under development since then. |
| The new back end, based on |
| <a href="https://en.wikipedia.org/wiki/Static_single_assignment_form">SSA</a>, |
| generates more compact, more efficient code |
| and provides a better platform for optimizations |
| such as bounds check elimination. |
| The new back end reduces the CPU time required by |
| <a href="/test/bench/go1/">our benchmark programs</a> by 5-35%. |
| </p> |
| |
| <p> |
| For this release, the new back end can be disabled by passing |
| <code>-ssa=0</code> to the compiler. |
| If you find that your program compiles or runs successfully |
| only with the new back end disabled, please |
| <a href="/issue/new">file a bug report</a>. |
| </p> |
| |
| <p> |
| The format of exported metadata written by the compiler in package archives has changed: |
| the old textual format has been replaced by a more compact binary format. |
| This results in somewhat smaller package archives and fixes a few |
| long-standing corner case bugs. |
| </p> |
| |
| <p> |
| For this release, the new export format can be disabled by passing |
| <code>-newexport=0</code> to the compiler. |
| If you find that your program compiles or runs successfully |
| only with the new export format disabled, please |
| <a href="/issue/new">file a bug report</a>. |
| </p> |
| |
| <p> |
| The linker's <code>-X</code> option no longer supports the unusual two-argument form |
| <code>-X</code> <code>name</code> <code>value</code>, |
| as <a href="/doc/go1.6#compiler">announced</a> in the Go 1.6 release |
| and in warnings printed by the linker. |
| Use <code>-X</code> <code>name=value</code> instead. |
| </p> |
| |
| <p> |
| The compiler and linker have been optimized and run significantly faster in this release than in Go 1.6, |
| although they are still slower than we would like and will continue to be optimized in future releases. |
| </p> |
| |
| <p> |
| Due to changes across the compiler toolchain and standard library, |
| binaries built with this release should typically be smaller than binaries |
| built with Go 1.6, |
| sometimes by as much as 20-30%. |
| </p> |
| |
| <p> |
| On x86-64 systems, Go programs now maintain stack frame pointers |
| as expected by profiling tools like Linux's perf and Intel's VTune, |
| making it easier to analyze and optimize Go programs using these tools. |
| The frame pointer maintenance has a small run-time overhead that varies |
| but averages around 2%. We hope to reduce this cost in future releases. |
| To build a toolchain that does not use frame pointers, set |
| <code>GOEXPERIMENT=noframepointer</code> when running |
| <code>make.bash</code>, <code>make.bat</code>, or <code>make.rc</code>. |
| </p> |
| |
| <h3 id="cmd_cgo">Cgo</h3> |
| |
| <p> |
| Packages using <a href="/cmd/cgo/">cgo</a> may now include |
| Fortran source files (in addition to C, C++, Objective C, and SWIG), |
| although the Go bindings must still use C language APIs. |
| </p> |
| |
| <p> |
| Go bindings may now use a new helper function <code>C.CBytes</code>. |
| In contrast to <code>C.CString</code>, which takes a Go <code>string</code> |
| and returns a <code>*C.byte</code> (a C <code>char*</code>), |
| <code>C.CBytes</code> takes a Go <code>[]byte</code> |
| and returns an <code>unsafe.Pointer</code> (a C <code>void*</code>). |
| </p> |
| |
| <p> |
| Packages and binaries built using <code>cgo</code> have in past releases |
| produced different output on each build, |
| due to the embedding of temporary directory names. |
| When using this release with |
| new enough versions of GCC or Clang |
| (those that support the <code>-fdebug-prefix-map</code> option), |
| those builds should finally be deterministic. |
| </p> |
| |
| <h3 id="gccgo">Gccgo</h3> |
| |
| <p> |
| Due to the alignment of Go's semiannual release schedule with GCC's annual release schedule, |
| GCC release 6 contains the Go 1.6.1 version of gccgo. |
| The next release, GCC 7, will likely have the Go 1.8 version of gccgo. |
| </p> |
| |
| <h3 id="cmd_go">Go command</h3> |
| |
| <p> |
| The <a href="/cmd/go/"><code>go</code></a> command's basic operation |
| is unchanged, but there are a number of changes worth noting. |
| </p> |
| |
| <p> |
| This release removes support for the <code>GO15VENDOREXPERIMENT</code> environment variable, |
| as <a href="/doc/go1.6#go_command">announced</a> in the Go 1.6 release. |
| <a href="/s/go15vendor">Vendoring support</a> |
| is now a standard feature of the <code>go</code> command and toolchain. |
| </p> |
| |
| <p> |
| The <code>Package</code> data structure made available to |
| “<code>go</code> <code>list</code>” now includes a |
| <code>StaleReason</code> field explaining why a particular package |
| is or is not considered stale (in need of rebuilding). |
| This field is available to the <code>-f</code> or <code>-json</code> |
| options and is useful for understanding why a target is being rebuilt. |
| </p> |
| |
| <p> |
| The “<code>go</code> <code>get</code>” command now supports |
| import paths referring to <code>git.openstack.org</code>. |
| </p> |
| |
| <p> |
| This release adds experimental, minimal support for building programs using |
| <a href="/pkg/go/build#hdr-Binary_Only_Packages">binary-only packages</a>, |
| packages distributed in binary form |
| without the corresponding source code. |
| This feature is needed in some commercial settings |
| but is not intended to be fully integrated into the rest of the toolchain. |
| For example, tools that assume access to complete source code |
| will not work with such packages, and there are no plans to support |
| such packages in the “<code>go</code> <code>get</code>” command. |
| </p> |
| |
| <h3 id="cmd_doc">Go doc</h3> |
| |
| <p> |
| The “<code>go</code> <code>doc</code>” command |
| now groups constructors with the type they construct, |
| following <a href="/cmd/godoc/"><code>godoc</code></a>. |
| </p> |
| |
| <h3 id="cmd_vet">Go vet</h3> |
| |
| <p> |
| The “<code>go</code> <code>vet</code>” command |
| has more accurate analysis in its <code>-copylock</code> and <code>-printf</code> checks, |
| and a new <code>-tests</code> check that checks the name and signature of likely test functions. |
| To avoid confusion with the new <code>-tests</code> check, the old, unadvertised |
| <code>-test</code> option has been removed; it was equivalent to <code>-all</code> <code>-shadow</code>. |
| </p> |
| |
| <p id="vet_lostcancel"> |
| The <code>vet</code> command also has a new check, |
| <code>-lostcancel</code>, which detects failure to call the |
| cancellation function returned by the <code>WithCancel</code>, |
| <code>WithTimeout</code>, and <code>WithDeadline</code> functions in |
| Go 1.7's new <code>context</code> package (see <a |
| href='#context'>below</a>). |
| Failure to call the function prevents the new <code>Context</code> |
| from being reclaimed until its parent is canceled. |
| (The background context is never canceled.) |
| </p> |
| |
| <h3 id="cmd_dist">Go tool dist</h3> |
| |
| <p> |
| The new subcommand “<code>go</code> <code>tool</code> <code>dist</code> <code>list</code>” |
| prints all supported operating system/architecture pairs. |
| </p> |
| |
| <h3 id="cmd_trace">Go tool trace</h3> |
| |
| <p> |
| The “<code>go</code> <code>tool</code> <code>trace</code>” command, |
| <a href="/doc/go1.5#trace_command">introduced in Go 1.5</a>, |
| has been refined in various ways. |
| </p> |
| |
| <p> |
| First, collecting traces is significantly more efficient than in past releases. |
| In this release, the typical execution-time overhead of collecting a trace is about 25%; |
| in past releases it was at least 400%. |
| Second, trace files now include file and line number information, |
| making them more self-contained and making the |
| original executable optional when running the trace tool. |
| Third, the trace tool now breaks up large traces to avoid limits |
| in the browser-based viewer. |
| </p> |
| |
| <p> |
| Although the trace file format has changed in this release, |
| the Go 1.7 tools can still read traces from earlier releases. |
| </p> |
| |
| <h2 id="performance">Performance</h2> |
| |
| <p> |
| As always, the changes are so general and varied that precise statements |
| about performance are difficult to make. |
| Most programs should run a bit faster, |
| due to speedups in the garbage collector and |
| optimizations in the core library. |
| On x86-64 systems, many programs will run significantly faster, |
| due to improvements in generated code brought by the |
| new compiler back end. |
| As noted above, in our own benchmarks, |
| the code generation changes alone typically reduce program CPU time by 5-35%. |
| </p> |
| |
| <p> |
| <!-- git log -''-grep '-[0-9][0-9]\.[0-9][0-9]%' go1.6.. --> |
| There have been significant optimizations bringing more than 10% improvements |
| to implementations in the |
| <a href="/pkg/crypto/sha1/"><code>crypto/sha1</code></a>, |
| <a href="/pkg/crypto/sha256/"><code>crypto/sha256</code></a>, |
| <a href="/pkg/encoding/binary/"><code>encoding/binary</code></a>, |
| <a href="/pkg/fmt/"><code>fmt</code></a>, |
| <a href="/pkg/hash/adler32/"><code>hash/adler32</code></a>, |
| <a href="/pkg/hash/crc32/"><code>hash/crc32</code></a>, |
| <a href="/pkg/hash/crc64/"><code>hash/crc64</code></a>, |
| <a href="/pkg/image/color/"><code>image/color</code></a>, |
| <a href="/pkg/math/big/"><code>math/big</code></a>, |
| <a href="/pkg/strconv/"><code>strconv</code></a>, |
| <a href="/pkg/strings/"><code>strings</code></a>, |
| <a href="/pkg/unicode/"><code>unicode</code></a>, |
| and |
| <a href="/pkg/unicode/utf16/"><code>unicode/utf16</code></a> |
| packages. |
| </p> |
| |
| <p> |
| Garbage collection pauses should be significantly shorter than they |
| were in Go 1.6 for programs with large numbers of idle goroutines, |
| substantial stack size fluctuation, or large package-level variables. |
| </p> |
| |
| <h2 id="library">Core library</h2> |
| |
| <h3 id="context">Context</h3> |
| |
| <p> |
| Go 1.7 moves the <code>golang.org/x/net/context</code> package |
| into the standard library as <a href="/pkg/context/"><code>context</code></a>. |
| This allows the use of contexts for cancellation, timeouts, and passing |
| request-scoped data in other standard library packages, |
| including |
| <a href="#net">net</a>, |
| <a href="#net_http">net/http</a>, |
| and |
| <a href="#os_exec">os/exec</a>, |
| as noted below. |
| </p> |
| |
| <p> |
| For more information about contexts, see the |
| <a href="/pkg/context/">package documentation</a> |
| and the Go blog post |
| “<a href="https://blog.golang.org/context">Go Concurrent Patterns: Context</a>.” |
| </p> |
| |
| <h3 id="httptrace">HTTP Tracing</h3> |
| |
| <p> |
| Go 1.7 introduces <a href="/pkg/net/http/httptrace/"><code>net/http/httptrace</code></a>, |
| a package that provides mechanisms for tracing events within HTTP requests. |
| </p> |
| |
| <h3 id="testing">Testing</h3> |
| |
| <p> |
| The <code>testing</code> package now supports the definition |
| of tests with subtests and benchmarks with sub-benchmarks. |
| This support makes it easy to write table-driven benchmarks |
| and to create hierarchical tests. |
| It also provides a way to share common setup and tear-down code. |
| See the <a href="/pkg/testing/#hdr-Subtests_and_Sub_benchmarks">package documentation</a> for details. |
| </p> |
| |
| <h3 id="runtime">Runtime</h3> |
| |
| <p> |
| All panics started by the runtime now use panic values |
| that implement both the |
| builtin <a href="/ref/spec#Errors"><code>error</code></a>, |
| and |
| <a href="/pkg/runtime/#Error"><code>runtime.Error</code></a>, |
| as |
| <a href="/ref/spec#Run_time_panics">required by the language specification</a>. |
| </p> |
| |
| <p> |
| During panics, if a signal's name is known, it will be printed in the stack trace. |
| Otherwise, the signal's number will be used, as it was before Go1.7. |
| </p> |
| |
| <p> |
| The new function |
| <a href="/pkg/runtime/#KeepAlive"><code>KeepAlive</code></a> |
| provides an explicit mechanism for declaring |
| that an allocated object must be considered reachable |
| at a particular point in a program, |
| typically to delay the execution of an associated finalizer. |
| </p> |
| |
| <p> |
| The new function |
| <a href="/pkg/runtime/#CallersFrames"><code>CallersFrames</code></a> |
| translates a PC slice obtained from |
| <a href="/pkg/runtime/#Callers"><code>Callers</code></a> |
| into a sequence of frames corresponding to the call stack. |
| This new API should be preferred instead of direct use of |
| <a href="/pkg/runtime/#FuncForPC"><code>FuncForPC</code></a>, |
| because the frame sequence can more accurately describe |
| call stacks with inlined function calls. |
| </p> |
| |
| <p> |
| The new function |
| <a href="/pkg/runtime/#SetCgoTraceback"><code>SetCgoTraceback</code></a> |
| facilitates tighter integration between Go and C code executing |
| in the same process called using cgo. |
| </p> |
| |
| <p> |
| On 32-bit systems, the runtime can now use memory allocated |
| by the operating system anywhere in the address space, |
| eliminating the |
| “memory allocated by OS not in usable range” failure |
| common in some environments. |
| </p> |
| |
| <p> |
| The runtime can now return unused memory to the operating system on |
| all architectures. |
| In Go 1.6 and earlier, the runtime could not |
| release memory on ARM64, 64-bit PowerPC, or MIPS. |
| </p> |
| |
| <p> |
| On Windows, Go programs in Go 1.5 and earlier forced |
| the global Windows timer resolution to 1ms at startup |
| by calling <code>timeBeginPeriod(1)</code>. |
| Changing the global timer resolution caused problems on some systems, |
| and testing suggested that the call was not needed for good scheduler performance, |
| so Go 1.6 removed the call. |
| Go 1.7 brings the call back: under some workloads the call |
| is still needed for good scheduler performance. |
| </p> |
| |
| |
| <h3 id="minor_library_changes">Minor changes to the library</h3> |
| |
| <p> |
| As always, there are various minor changes and updates to the library, |
| made with the Go 1 <a href="/doc/go1compat">promise of compatibility</a> |
| in mind. |
| </p> |
| |
| <dl id="bufio"><dt><a href="/pkg/bufio/">bufio</a></dt> |
| |
| <dd> |
| <p> |
| In previous releases of Go, if |
| <a href="/pkg/bufio/#Reader"><code>Reader</code></a>'s |
| <a href="/pkg/bufio/#Reader.Peek"><code>Peek</code></a> method |
| were asked for more bytes than fit in the underlying buffer, |
| it would return an empty slice and the error <code>ErrBufferFull</code>. |
| Now it returns the entire underlying buffer, still accompanied by the error <code>ErrBufferFull</code>. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="bytes"><dt><a href="/pkg/bytes/">bytes</a></dt> |
| |
| <dd> |
| <p> |
| The new functions |
| <a href="/pkg/bytes/#ContainsAny"><code>ContainsAny</code></a> and |
| <a href="/pkg/bytes/#ContainsRune"><code>ContainsRune</code></a> |
| have been added for symmetry with |
| the <a href="/pkg/strings/"><code>strings</code></a> package. |
| </p> |
| |
| <p> |
| In previous releases of Go, if |
| <a href="/pkg/bytes/#Reader"><code>Reader</code></a>'s |
| <a href="/pkg/bytes/#Reader.Read"><code>Read</code></a> method |
| were asked for zero bytes with no data remaining, it would |
| return a count of 0 and no error. |
| Now it returns a count of 0 and the error |
| <a href="/pkg/io/#EOF"><code>io.EOF</code></a>. |
| </p> |
| |
| <p> |
| The |
| <a href="/pkg/bytes/#Reader"><code>Reader</code></a> type has a new method |
| <a href="/pkg/bytes/#Reader.Reset"><code>Reset</code></a> to allow reuse of a <code>Reader</code>. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="compress_flate"><dt><a href="/pkg/compress/flate/">compress/flate</a></dt> |
| |
| <dd> |
| <p> |
| There are many performance optimizations throughout the package. |
| Decompression speed is improved by about 10%, |
| while compression for <code>DefaultCompression</code> is twice as fast. |
| </p> |
| |
| <p> |
| In addition to those general improvements, |
| the |
| <code>BestSpeed</code> |
| compressor has been replaced entirely and uses an |
| algorithm similar to <a href="https://github.com/google/snappy">Snappy</a>, |
| resulting in about a 2.5X speed increase, |
| although the output can be 5-10% larger than with the previous algorithm. |
| </p> |
| |
| <p> |
| There is also a new compression level |
| <code>HuffmanOnly</code> |
| that applies Huffman but not Lempel-Ziv encoding. |
| <a href="https://blog.klauspost.com/constant-time-gzipzip-compression/">Forgoing Lempel-Ziv encoding</a> means that |
| <code>HuffmanOnly</code> runs about 3X faster than the new <code>BestSpeed</code> |
| but at the cost of producing compressed outputs that are 20-40% larger than those |
| generated by the new <code>BestSpeed</code>. |
| </p> |
| |
| <p> |
| It is important to note that both |
| <code>BestSpeed</code> and <code>HuffmanOnly</code> produce a compressed output that is |
| <a href="https://tools.ietf.org/html/rfc1951">RFC 1951</a> compliant. |
| In other words, any valid DEFLATE decompressor will continue to be able to decompress these outputs. |
| </p> |
| |
| <p> |
| Lastly, there is a minor change to the decompressor's implementation of |
| <a href="/pkg/io/#Reader"><code>io.Reader</code></a>. In previous versions, |
| the decompressor deferred reporting |
| <a href="/pkg/io/#EOF"><code>io.EOF</code></a> until exactly no more bytes could be read. |
| Now, it reports |
| <a href="/pkg/io/#EOF"><code>io.EOF</code></a> more eagerly when reading the last set of bytes. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="crypto_tls"><dt><a href="/pkg/crypto/tls/">crypto/tls</a></dt> |
| |
| <dd> |
| <p> |
| The TLS implementation sends the first few data packets on each connection |
| using small record sizes, gradually increasing to the TLS maximum record size. |
| This heuristic reduces the amount of data that must be received before |
| the first packet can be decrypted, improving communication latency over |
| low-bandwidth networks. |
| Setting |
| <a href="/pkg/crypto/tls/#Config"><code>Config</code></a>'s |
| <code>DynamicRecordSizingDisabled</code> field to true |
| forces the behavior of Go 1.6 and earlier, where packets are |
| as large as possible from the start of the connection. |
| </p> |
| |
| <p> |
| The TLS client now has optional, limited support for server-initiated renegotiation, |
| enabled by setting the |
| <a href="/pkg/crypto/tls/#Config"><code>Config</code></a>'s |
| <code>Renegotiation</code> field. |
| This is needed for connecting to many Microsoft Azure servers. |
| </p> |
| |
| <p> |
| The errors returned by the package now consistently begin with a |
| <code>tls:</code> prefix. |
| In past releases, some errors used a <code>crypto/tls:</code> prefix, |
| some used a <code>tls:</code> prefix, and some had no prefix at all. |
| </p> |
| |
| <p> |
| When generating self-signed certificates, the package no longer sets the |
| “Authority Key Identifier” field by default. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="crypto_x509"><dt><a href="/pkg/crypto/x509/">crypto/x509</a></dt> |
| |
| <dd> |
| <p> |
| The new function |
| <a href="/pkg/crypto/x509/#SystemCertPool"><code>SystemCertPool</code></a> |
| provides access to the entire system certificate pool if available. |
| There is also a new associated error type |
| <a href="/pkg/crypto/x509/#SystemRootsError"><code>SystemRootsError</code></a>. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="debug_dwarf"><dt><a href="/pkg/debug/dwarf/">debug/dwarf</a></dt> |
| |
| <dd> |
| <p> |
| The |
| <a href="/pkg/debug/dwarf/#Reader"><code>Reader</code></a> type's new |
| <a href="/pkg/debug/dwarf/#Reader.SeekPC"><code>SeekPC</code></a> method and the |
| <a href="/pkg/debug/dwarf/#Data"><code>Data</code></a> type's new |
| <a href="/pkg/debug/dwarf/#Ranges"><code>Ranges</code></a> method |
| help to find the compilation unit to pass to a |
| <a href="/pkg/debug/dwarf/#LineReader"><code>LineReader</code></a> |
| and to identify the specific function for a given program counter. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="debug_elf"><dt><a href="/pkg/debug/elf/">debug/elf</a></dt> |
| |
| <dd> |
| <p> |
| The new |
| <a href="/pkg/debug/elf/#R_390"><code>R_390</code></a> relocation type |
| and its many predefined constants |
| support the S390 port. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="encoding_asn1"><dt><a href="/pkg/encoding/asn1/">encoding/asn1</a></dt> |
| |
| <dd> |
| <p> |
| The ASN.1 decoder now rejects non-minimal integer encodings. |
| This may cause the package to reject some invalid but formerly accepted ASN.1 data. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="encoding_json"><dt><a href="/pkg/encoding/json/">encoding/json</a></dt> |
| |
| <dd> |
| <p> |
| The |
| <a href="/pkg/encoding/json/#Encoder"><code>Encoder</code></a>'s new |
| <a href="/pkg/encoding/json/#Encoder.SetIndent"><code>SetIndent</code></a> method |
| sets the indentation parameters for JSON encoding, |
| like in the top-level |
| <a href="/pkg/encoding/json/#Indent"><code>Indent</code></a> function. |
| </p> |
| |
| <p> |
| The |
| <a href="/pkg/encoding/json/#Encoder"><code>Encoder</code></a>'s new |
| <a href="/pkg/encoding/json/#Encoder.SetEscapeHTML"><code>SetEscapeHTML</code></a> method |
| controls whether the |
| <code>&</code>, <code><</code>, and <code>></code> |
| characters in quoted strings should be escaped as |
| <code>\u0026</code>, <code>\u003c</code>, and <code>\u003e</code>, |
| respectively. |
| As in previous releases, the encoder defaults to applying this escaping, |
| to avoid certain problems that can arise when embedding JSON in HTML. |
| </p> |
| |
| <p> |
| In earlier versions of Go, this package only supported encoding and decoding |
| maps using keys with string types. |
| Go 1.7 adds support for maps using keys with integer types: |
| the encoding uses a quoted decimal representation as the JSON key. |
| Go 1.7 also adds support for encoding maps using non-string keys that implement |
| the <code>MarshalText</code> |
| (see |
| <a href="/pkg/encoding/#TextMarshaler"><code>encoding.TextMarshaler</code></a>) |
| method, |
| as well as support for decoding maps using non-string keys that implement |
| the <code>UnmarshalText</code> |
| (see |
| <a href="/pkg/encoding/#TextUnmarshaler"><code>encoding.TextUnmarshaler</code></a>) |
| method. |
| These methods are ignored for keys with string types in order to preserve |
| the encoding and decoding used in earlier versions of Go. |
| </p> |
| |
| <p> |
| When encoding a slice of typed bytes, |
| <a href="/pkg/encoding/json/#Marshal"><code>Marshal</code></a> |
| now generates an array of elements encoded using |
| that byte type's |
| <code>MarshalJSON</code> |
| or |
| <code>MarshalText</code> |
| method if present, |
| only falling back to the default base64-encoded string data if neither method is available. |
| Earlier versions of Go accept both the original base64-encoded string encoding |
| and the array encoding (assuming the byte type also implements |
| <code>UnmarshalJSON</code> |
| or |
| <code>UnmarshalText</code> |
| as appropriate), |
| so this change should be semantically backwards compatible with earlier versions of Go, |
| even though it does change the chosen encoding. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="go_build"><dt><a href="/pkg/go/build/">go/build</a></dt> |
| |
| <dd> |
| <p> |
| To implement the go command's new support for binary-only packages |
| and for Fortran code in cgo-based packages, |
| the |
| <a href="/pkg/go/build/#Package"><code>Package</code></a> type |
| adds new fields <code>BinaryOnly</code>, <code>CgoFFLAGS</code>, and <code>FFiles</code>. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="go_doc"><dt><a href="/pkg/go/doc/">go/doc</a></dt> |
| |
| <dd> |
| <p> |
| To support the corresponding change in <code>go</code> <code>test</code> described above, |
| <a href="/pkg/go/doc/#Example"><code>Example</code></a> struct adds a Unordered field |
| indicating whether the example may generate its output lines in any order. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="io"><dt><a href="/pkg/io/">io</a></dt> |
| |
| <dd> |
| <p> |
| The package adds new constants |
| <code>SeekStart</code>, <code>SeekCurrent</code>, and <code>SeekEnd</code>, |
| for use with |
| <a href="/pkg/io/#Seeker"><code>Seeker</code></a> |
| implementations. |
| These constants are preferred over <code>os.SEEK_SET</code>, <code>os.SEEK_CUR</code>, and <code>os.SEEK_END</code>, |
| but the latter will be preserved for compatibility. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="math_big"><dt><a href="/pkg/math/big/">math/big</a></dt> |
| |
| <dd> |
| <p> |
| The |
| <a href="/pkg/math/big/#Float"><code>Float</code></a> type adds |
| <a href="/pkg/math/big/#Float.GobEncode"><code>GobEncode</code></a> and |
| <a href="/pkg/math/big/#Float.GobDecode"><code>GobDecode</code></a> methods, |
| so that values of type <code>Float</code> can now be encoded and decoded using the |
| <a href="/pkg/encoding/gob/"><code>encoding/gob</code></a> |
| package. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="math_rand"><dt><a href="/pkg/math/rand/">math/rand</a></dt> |
| |
| <dd> |
| <p> |
| The |
| <a href="/pkg/math/rand/#Read"><code>Read</code></a> function and |
| <a href="/pkg/math/rand/#Rand"><code>Rand</code></a>'s |
| <a href="/pkg/math/rand/#Rand.Read"><code>Read</code></a> method |
| now produce a pseudo-random stream of bytes that is consistent and not |
| dependent on the size of the input buffer. |
| </p> |
| |
| <p> |
| The documentation clarifies that |
| Rand's <a href="/pkg/math/rand/#Rand.Seed"><code>Seed</code></a> |
| and <a href="/pkg/math/rand/#Rand.Read"><code>Read</code></a> methods |
| are not safe to call concurrently, though the global |
| functions <a href="/pkg/math/rand/#Seed"><code>Seed</code></a> |
| and <a href="/pkg/math/rand/#Read"><code>Read</code></a> are (and have |
| always been) safe. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="mime_multipart"><dt><a href="/pkg/mime/multipart/">mime/multipart</a></dt> |
| |
| <dd> |
| <p> |
| The |
| <a href="/pkg/mime/multipart/#Writer"><code>Writer</code></a> |
| implementation now emits each multipart section's header sorted by key. |
| Previously, iteration over a map caused the section header to use a |
| non-deterministic order. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="net"><dt><a href="/pkg/net/">net</a></dt> |
| |
| <dd> |
| <p> |
| As part of the introduction of <a href="#context">context</a>, the |
| <a href="/pkg/net/#Dialer"><code>Dialer</code></a> type has a new method |
| <a href="/pkg/net/#Dialer.DialContext"><code>DialContext</code></a>, like |
| <a href="/pkg/net/#Dialer.Dial"><code>Dial</code></a> but adding the |
| <a href="/pkg/context/#Context"><code>context.Context</code></a> |
| for the dial operation. |
| The context is intended to obsolete the <code>Dialer</code>'s |
| <code>Cancel</code> and <code>Deadline</code> fields, |
| but the implementation continues to respect them, |
| for backwards compatibility. |
| </p> |
| |
| <p> |
| The |
| <a href="/pkg/net/#IP"><code>IP</code></a> type's |
| <a href="/pkg/net/#IP.String"><code>String</code></a> method has changed its result for invalid <code>IP</code> addresses. |
| In past releases, if an <code>IP</code> byte slice had length other than 0, 4, or 16, <code>String</code> |
| returned <code>"?"</code>. |
| Go 1.7 adds the hexadecimal encoding of the bytes, as in <code>"?12ab"</code>. |
| </p> |
| |
| <p> |
| The pure Go <a href="/pkg/net/#hdr-Name_Resolution">name resolution</a> |
| implementation now respects <code>nsswitch.conf</code>'s |
| stated preference for the priority of DNS lookups compared to |
| local file (that is, <code>/etc/hosts</code>) lookups. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="net_http"><dt><a href="/pkg/net/http/">net/http</a></dt> |
| |
| <dd> |
| <p> |
| <a href="/pkg/net/http/#ResponseWriter"><code>ResponseWriter</code></a>'s |
| documentation now makes clear that beginning to write the response |
| may prevent future reads on the request body. |
| For maximal compatibility, implementations are encouraged to |
| read the request body completely before writing any part of the response. |
| </p> |
| |
| <p> |
| As part of the introduction of <a href="#context">context</a>, the |
| <a href="/pkg/net/http/#Request"><code>Request</code></a> has a new methods |
| <a href="/pkg/net/http/#Request.Context"><code>Context</code></a>, to retrieve the associated context, and |
| <a href="/pkg/net/http/#Request.WithContext"><code>WithContext</code></a>, to construct a copy of <code>Request</code> |
| with a modified context. |
| </p> |
| |
| <p> |
| In the |
| <a href="/pkg/net/http/#Server"><code>Server</code></a> implementation, |
| <a href="/pkg/net/http/#Server.Serve"><code>Serve</code></a> records in the request context |
| both the underlying <code>*Server</code> using the key <code>ServerContextKey</code> |
| and the local address on which the request was received (a |
| <a href="/pkg/net/#Addr"><code>Addr</code></a>) using the key <code>LocalAddrContextKey</code>. |
| For example, the address on which a request received is |
| <code>req.Context().Value(http.LocalAddrContextKey).(net.Addr)</code>. |
| </p> |
| |
| <p> |
| The server's <a href="/pkg/net/http/#Server.Serve"><code>Serve</code></a> method |
| now only enables HTTP/2 support if the <code>Server.TLSConfig</code> field is <code>nil</code> |
| or includes <code>"h2"</code> in its <code>TLSConfig.NextProtos</code>. |
| </p> |
| |
| <p> |
| The server implementation now |
| pads response codes less than 100 to three digits |
| as required by the protocol, |
| so that <code>w.WriteHeader(5)</code> uses the HTTP response |
| status <code>005</code>, not just <code>5</code>. |
| </p> |
| |
| <p> |
| The server implementation now correctly sends only one "Transfer-Encoding" header when "chunked" |
| is set explicitly, following <a href="https://tools.ietf.org/html/rfc7230#section-3.3.1">RFC 7230</a>. |
| </p> |
| |
| <p> |
| The server implementation is now stricter about rejecting requests with invalid HTTP versions. |
| Invalid requests claiming to be HTTP/0.x are now rejected (HTTP/0.9 was never fully supported), |
| and plaintext HTTP/2 requests other than the "PRI * HTTP/2.0" upgrade request are now rejected as well. |
| The server continues to handle encrypted HTTP/2 requests. |
| </p> |
| |
| <p> |
| In the server, a 200 status code is sent back by the timeout handler on an empty |
| response body, instead of sending back 0 as the status code. |
| </p> |
| |
| <p> |
| In the client, the |
| <a href="/pkg/net/http/#Transport"><code>Transport</code></a> implementation passes the request context |
| to any dial operation connecting to the remote server. |
| If a custom dialer is needed, the new <code>Transport</code> field |
| <code>DialContext</code> is preferred over the existing <code>Dial</code> field, |
| to allow the transport to supply a context. |
| </p> |
| |
| <p> |
| The |
| <a href="/pkg/net/http/#Transport"><code>Transport</code></a> also adds fields |
| <code>IdleConnTimeout</code>, |
| <code>MaxIdleConns</code>, |
| and |
| <code>MaxResponseHeaderBytes</code> |
| to help control client resources consumed |
| by idle or chatty servers. |
| </p> |
| |
| <p> |
| A |
| <a href="/pkg/net/http/#Client"><code>Client</code></a>'s configured <code>CheckRedirect</code> function can now |
| return <code>ErrUseLastResponse</code> to indicate that the |
| most recent redirect response should be returned as the |
| result of the HTTP request. |
| That response is now available to the <code>CheckRedirect</code> function |
| as <code>req.Response</code>. |
| </p> |
| |
| <p> |
| Since Go 1, the default behavior of the HTTP client is |
| to request server-side compression |
| using the <code>Accept-Encoding</code> request header |
| and then to decompress the response body transparently, |
| and this behavior is adjustable using the |
| <a href="/pkg/net/http/#Transport"><code>Transport</code></a>'s <code>DisableCompression</code> field. |
| In Go 1.7, to aid the implementation of HTTP proxies, the |
| <a href="/pkg/net/http/#Response"><code>Response</code></a>'s new |
| <code>Uncompressed</code> field reports whether |
| this transparent decompression took place. |
| </p> |
| |
| <p> |
| <a href="/pkg/net/http/#DetectContentType"><code>DetectContentType</code></a> |
| adds support for a few new audio and video content types. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="net_http_cgi"><dt><a href="/pkg/net/http/cgi/">net/http/cgi</a></dt> |
| |
| <dd> |
| <p> |
| The |
| <a href="/pkg/net/http/cgi/#Handler"><code>Handler</code></a> |
| adds a new field |
| <code>Stderr</code> |
| that allows redirection of the child process's |
| standard error away from the host process's |
| standard error. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="net_http_httptest"><dt><a href="/pkg/net/http/httptest/">net/http/httptest</a></dt> |
| |
| <dd> |
| <p> |
| The new function |
| <a href="/pkg/net/http/httptest/#NewRequest"><code>NewRequest</code></a> |
| prepares a new |
| <a href="/pkg/net/http/#Request"><code>http.Request</code></a> |
| suitable for passing to an |
| <a href="/pkg/net/http/#Handler"><code>http.Handler</code></a> during a test. |
| </p> |
| |
| <p> |
| The |
| <a href="/pkg/net/http/httptest/#ResponseRecorder"><code>ResponseRecorder</code></a>'s new |
| <a href="/pkg/net/http/httptest/#ResponseRecorder.Result"><code>Result</code></a> method |
| returns the recorded |
| <a href="/pkg/net/http/#Response"><code>http.Response</code></a>. |
| Tests that need to check the response's headers or trailers |
| should call <code>Result</code> and inspect the response fields |
| instead of accessing |
| <code>ResponseRecorder</code>'s <code>HeaderMap</code> directly. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="net_http_httputil"><dt><a href="/pkg/net/http/httputil/">net/http/httputil</a></dt> |
| |
| <dd> |
| <p> |
| The |
| <a href="/pkg/net/http/httputil/#ReverseProxy"><code>ReverseProxy</code></a> implementation now responds with “502 Bad Gateway” |
| when it cannot reach a back end; in earlier releases it responded with “500 Internal Server Error.” |
| </p> |
| |
| <p> |
| Both |
| <a href="/pkg/net/http/httputil/#ClientConn"><code>ClientConn</code></a> and |
| <a href="/pkg/net/http/httputil/#ServerConn"><code>ServerConn</code></a> have been documented as deprecated. |
| They are low-level, old, and unused by Go's current HTTP stack |
| and will no longer be updated. |
| Programs should use |
| <a href="/pkg/net/http/#Client"><code>http.Client</code></a>, |
| <a href="/pkg/net/http/#Transport"><code>http.Transport</code></a>, |
| and |
| <a href="/pkg/net/http/#Server"><code>http.Server</code></a> |
| instead. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="net_http_pprof"><dt><a href="/pkg/net/http/pprof/">net/http/pprof</a></dt> |
| |
| <dd> |
| <p> |
| The runtime trace HTTP handler, installed to handle the path <code>/debug/pprof/trace</code>, |
| now accepts a fractional number in its <code>seconds</code> query parameter, |
| allowing collection of traces for intervals smaller than one second. |
| This is especially useful on busy servers. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl><dt><a href="/pkg/net/mail/">net/mail</a></dt> |
| |
| <dd> |
| <p> |
| The address parser now allows unescaped UTF-8 text in addresses |
| following <a href="https://tools.ietf.org/html/rfc6532">RFC 6532</a>, |
| but it does not apply any normalization to the result. |
| For compatibility with older mail parsers, |
| the address encoder, namely |
| <a href="/pkg/net/mail/#Address"><code>Address</code></a>'s |
| <a href="/pkg/net/mail/#Address.String"><code>String</code></a> method, |
| continues to escape all UTF-8 text following <a href="https://tools.ietf.org/html/rfc5322">RFC 5322</a>. |
| </p> |
| |
| <p> |
| The <a href="/pkg/net/mail/#ParseAddress"><code>ParseAddress</code></a> |
| function and |
| the <a href="/pkg/net/mail/#AddressParser.Parse"><code>AddressParser.Parse</code></a> |
| method are stricter. |
| They used to ignore any characters following an e-mail address, but |
| will now return an error for anything other than whitespace. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="net_url"><dt><a href="/pkg/net/url/">net/url</a></dt> |
| |
| <dd> |
| <p> |
| The |
| <a href="/pkg/net/url/#URL"><code>URL</code></a>'s |
| new <code>ForceQuery</code> field |
| records whether the URL must have a query string, |
| in order to distinguish URLs without query strings (like <code>/search</code>) |
| from URLs with empty query strings (like <code>/search?</code>). |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="os"><dt><a href="/pkg/os/">os</a></dt> |
| |
| <dd> |
| <p> |
| <a href="/pkg/os/#IsExist"><code>IsExist</code></a> now returns true for <code>syscall.ENOTEMPTY</code>, |
| on systems where that error exists. |
| </p> |
| |
| <p> |
| On Windows, |
| <a href="/pkg/os/#Remove"><code>Remove</code></a> now removes read-only files when possible, |
| making the implementation behave as on |
| non-Windows systems. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="os_exec"><dt><a href="/pkg/os/exec/">os/exec</a></dt> |
| |
| <dd> |
| <p> |
| As part of the introduction of <a href="#context">context</a>, |
| the new constructor |
| <a href="/pkg/os/exec/#CommandContext"><code>CommandContext</code></a> |
| is like |
| <a href="/pkg/os/exec/#Command"><code>Command</code></a> but includes a context that can be used to cancel the command execution. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="os_user"><dt><a href="/pkg/os/user/">os/user</a></dt> |
| |
| <dd> |
| <p> |
| The |
| <a href="/pkg/os/user/#Current"><code>Current</code></a> |
| function is now implemented even when cgo is not available. |
| </p> |
| |
| <p> |
| The new |
| <a href="/pkg/os/user/#Group"><code>Group</code></a> type, |
| along with the lookup functions |
| <a href="/pkg/os/user/#LookupGroup"><code>LookupGroup</code></a> and |
| <a href="/pkg/os/user/#LookupGroupId"><code>LookupGroupId</code></a> |
| and the new field <code>GroupIds</code> in the <code>User</code> struct, |
| provides access to system-specific user group information. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="reflect"><dt><a href="/pkg/reflect/">reflect</a></dt> |
| |
| <dd> |
| <p> |
| Although |
| <a href="/pkg/reflect/#Value"><code>Value</code></a>'s |
| <a href="/pkg/reflect/#Value.Field"><code>Field</code></a> method has always been documented to panic |
| if the given field number <code>i</code> is out of range, it has instead |
| silently returned a zero |
| <a href="/pkg/reflect/#Value"><code>Value</code></a>. |
| Go 1.7 changes the method to behave as documented. |
| </p> |
| |
| <p> |
| The new |
| <a href="/pkg/reflect/#StructOf"><code>StructOf</code></a> |
| function constructs a struct type at run time. |
| It completes the set of type constructors, joining |
| <a href="/pkg/reflect/#ArrayOf"><code>ArrayOf</code></a>, |
| <a href="/pkg/reflect/#ChanOf"><code>ChanOf</code></a>, |
| <a href="/pkg/reflect/#FuncOf"><code>FuncOf</code></a>, |
| <a href="/pkg/reflect/#MapOf"><code>MapOf</code></a>, |
| <a href="/pkg/reflect/#PtrTo"><code>PtrTo</code></a>, |
| and |
| <a href="/pkg/reflect/#SliceOf"><code>SliceOf</code></a>. |
| </p> |
| |
| <p> |
| <a href="/pkg/reflect/#StructTag"><code>StructTag</code></a>'s |
| new method |
| <a href="/pkg/reflect/#StructTag.Lookup"><code>Lookup</code></a> |
| is like |
| <a href="/pkg/reflect/#StructTag.Get"><code>Get</code></a> |
| but distinguishes the tag not containing the given key |
| from the tag associating an empty string with the given key. |
| </p> |
| |
| <p> |
| The |
| <a href="/pkg/reflect/#Type.Method"><code>Method</code></a> and |
| <a href="/pkg/reflect/#Type.NumMethod"><code>NumMethod</code></a> |
| methods of |
| <a href="/pkg/reflect/#Type"><code>Type</code></a> and |
| <a href="/pkg/reflect/#Value"><code>Value</code></a> |
| no longer return or count unexported methods. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="strings"><dt><a href="/pkg/strings/">strings</a></dt> |
| |
| <dd> |
| <p> |
| In previous releases of Go, if |
| <a href="/pkg/strings/#Reader"><code>Reader</code></a>'s |
| <a href="/pkg/strings/#Reader.Read"><code>Read</code></a> method |
| were asked for zero bytes with no data remaining, it would |
| return a count of 0 and no error. |
| Now it returns a count of 0 and the error |
| <a href="/pkg/io/#EOF"><code>io.EOF</code></a>. |
| </p> |
| |
| <p> |
| The |
| <a href="/pkg/strings/#Reader"><code>Reader</code></a> type has a new method |
| <a href="/pkg/strings/#Reader.Reset"><code>Reset</code></a> to allow reuse of a <code>Reader</code>. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="time"><dt><a href="/pkg/time/">time</a></dt> |
| |
| <dd> |
| <p> |
| <a href="/pkg/time/#Duration"><code>Duration</code></a>'s |
| time.Duration.String method now reports the zero duration as <code>"0s"</code>, not <code>"0"</code>. |
| <a href="/pkg/time/#ParseDuration"><code>ParseDuration</code></a> continues to accept both forms. |
| </p> |
| |
| <p> |
| The method call <code>time.Local.String()</code> now returns <code>"Local"</code> on all systems; |
| in earlier releases, it returned an empty string on Windows. |
| </p> |
| |
| <p> |
| The time zone database in |
| <code>$GOROOT/lib/time</code> has been updated |
| to IANA release 2016d. |
| This fallback database is only used when the system time zone database |
| cannot be found, for example on Windows. |
| The Windows time zone abbreviation list has also been updated. |
| </p> |
| </dd> |
| </dl> |
| |
| <dl id="syscall"><dt><a href="/pkg/syscall/">syscall</a></dt> |
| |
| <dd> |
| <p> |
| On Linux, the |
| <a href="/pkg/syscall/#SysProcAttr"><code>SysProcAttr</code></a> struct |
| (as used in |
| <a href="/pkg/os/exec/#Cmd"><code>os/exec.Cmd</code></a>'s <code>SysProcAttr</code> field) |
| has a new <code>Unshareflags</code> field. |
| If the field is nonzero, the child process created by |
| <a href="/pkg/syscall/#ForkExec"><code>ForkExec</code></a> |
| (as used in <code>exec.Cmd</code>'s <code>Run</code> method) |
| will call the |
| <a href="http://man7.org/linux/man-pages/man2/unshare.2.html"><i>unshare</i>(2)</a> |
| system call before executing the new program. |
| </p> |
| </dd> |
| </dl> |
| |
| |
| <dl id="unicode"><dt><a href="/pkg/unicode/">unicode</a></dt> |
| |
| <dd> |
| <p> |
| The <a href="/pkg/unicode/"><code>unicode</code></a> package and associated |
| support throughout the system has been upgraded from version 8.0 to |
| <a href="http://www.unicode.org/versions/Unicode9.0.0/">Unicode 9.0</a>. |
| </p> |
| </dd> |
| </dl> |