* doc/xml/manual/diagnostics.xml: Document use of errno.
* doc/html/*: Regenerate.
* config/locale/generic/c_locale.cc (_Save_errno): New helper.
(__convert_to_v): Use _Save_errno.
* include/ext/string_conversions.h (__stoa): Only restore errno when
it isn't set to non-zero.
From-SVN: r228328
+2015-10-01 Jonathan Wakely <jwakely@redhat.com>
+
+ * doc/xml/manual/diagnostics.xml: Document use of errno.
+ * doc/html/*: Regenerate.
+ * config/locale/generic/c_locale.cc (_Save_errno): New helper.
+ (__convert_to_v): Use _Save_errno.
+ * include/ext/string_conversions.h (__stoa): Only restore errno when
+ it isn't set to non-zero.
+
2015-09-30 François Dumont <fdumont@gcc.gnu.org>
Jonathan Wakely <jwakely@redhat.com>
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
+ namespace
+ {
+ struct _Save_errno
+ {
+ _Save_errno() : _M_errno(errno) { errno = 0; }
+ ~_Save_errno() { if (errno == 0) errno = _M_errno; }
+ int _M_errno;
+ };
+ }
+
template<>
void
__convert_to_v(const char* __s, float& __v, ios_base::iostate& __err,
bool __overflow = false;
#if !__FLT_HAS_INFINITY__
- errno = 0;
+ const _Save_errno __save_errno;
#endif
#ifdef _GLIBCXX_HAVE_STRTOF
char* __sanity;
#if !__DBL_HAS_INFINITY__
- errno = 0;
+ const _Save_errno __save_errno;
#endif
__v = strtod(__s, &__sanity);
setlocale(LC_ALL, "C");
#if !__LDBL_HAS_INFINITY__
- errno = 0;
+ const _Save_errno __save_errno;
#endif
#if defined(_GLIBCXX_HAVE_STRTOLD) && !defined(_GLIBCXX_HAVE_BROKEN_STRTOLD)
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Concept Checking</title><meta name="generator" content="DocBook XSL-NS Stylesheets V1.78.1" /><meta name="keywords" content="ISO C++, library" /><meta name="keywords" content="ISO C++, runtime, library" /><link rel="home" href="../index.html" title="The GNU C++ Library" /><link rel="up" href="diagnostics.html" title="Chapter 5. Diagnostics" /><link rel="prev" href="diagnostics.html" title="Chapter 5. Diagnostics" /><link rel="next" href="utilities.html" title="Chapter 6. Utilities" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Concept Checking</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="diagnostics.html">Prev</a> </td><th width="60%" align="center">Chapter 5.
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Concept Checking</title><meta name="generator" content="DocBook XSL-NS Stylesheets V1.78.1" /><meta name="keywords" content="ISO C++, library" /><meta name="keywords" content="ISO C++, runtime, library" /><link rel="home" href="../index.html" title="The GNU C++ Library" /><link rel="up" href="diagnostics.html" title="Chapter 5. Diagnostics" /><link rel="prev" href="errno.html" title="Use of errno by the library" /><link rel="next" href="utilities.html" title="Chapter 6. Utilities" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Concept Checking</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="errno.html">Prev</a> </td><th width="60%" align="center">Chapter 5.
Diagnostics
</th><td width="20%" align="right"> <a accesskey="n" href="utilities.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="std.diagnostics.concept_checking"></a>Concept Checking</h2></div></div></div><p>
for example template argument types may need to be complete when used in
a template definition, rather than at the point of instantiation.
There are no plans to address these shortcomings.
- </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="diagnostics.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="diagnostics.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="utilities.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 5.
- Diagnostics
-
- </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 6.
+ </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="errno.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="diagnostics.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="utilities.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Use of errno by the library </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 6.
Utilities
</td></tr></table></div></body></html>
\ No newline at end of file
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Chapter 5. Diagnostics</title><meta name="generator" content="DocBook XSL-NS Stylesheets V1.78.1" /><meta name="keywords" content="ISO C++, library" /><meta name="keywords" content="ISO C++, runtime, library" /><link rel="home" href="../index.html" title="The GNU C++ Library" /><link rel="up" href="std_contents.html" title="Part II. Standard Contents" /><link rel="prev" href="termination.html" title="Termination" /><link rel="next" href="
concept_checking.html" title="Concept Checking" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 5.
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Chapter 5. Diagnostics</title><meta name="generator" content="DocBook XSL-NS Stylesheets V1.78.1" /><meta name="keywords" content="ISO C++, library" /><meta name="keywords" content="ISO C++, runtime, library" /><link rel="home" href="../index.html" title="The GNU C++ Library" /><link rel="up" href="std_contents.html" title="Part II. Standard Contents" /><link rel="prev" href="termination.html" title="Termination" /><link rel="next" href="
errno.html" title="Use of errno by the library" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 5.
Diagnostics
</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="termination.html">Prev</a> </td><th width="60%" align="center">Part II.
Standard Contents
- </th><td width="20%" align="right"> <a accesskey="n" href="
concept_checking.html">Next</a></td></tr></table><hr /></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="std.diagnostics"></a>Chapter 5.
+ </th><td width="20%" align="right"> <a accesskey="n" href="
errno.html">Next</a></td></tr></table><hr /></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="std.diagnostics"></a>Chapter 5.
Diagnostics
<a id="id-1.3.4.3.1.1.1" class="indexterm"></a>
-</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions">Exceptions</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.api">API Reference</a></span></dt><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.data">Adding Data to <code class="classname">exception</code></a></span></dt></dl></dd><dt><span class="section"><a href="concept_checking.html">Concept Checking</a></span></dt></dl></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="std.diagnostics.exceptions"></a>Exceptions</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="std.diagnostics.exceptions.api"></a>API Reference</h3></div></div></div><p>
+</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions">Exceptions</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.api">API Reference</a></span></dt><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.data">Adding Data to <code class="classname">exception</code></a></span></dt></dl></dd><dt><span class="section"><a href="
errno.html">Use of errno by the library</a></span></dt><dt><span class="section"><a href="concept_checking.html">Concept Checking</a></span></dt></dl></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="std.diagnostics.exceptions"></a>Exceptions</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="std.diagnostics.exceptions.api"></a>API Reference</h3></div></div></div><p>
All exception objects are defined in one of the standard header
files: <code class="filename">exception</code>,
<code class="filename">stdexcept</code>, <code class="filename">new</code>, and
int e;
DBID id; // some user-defined type
};
- </pre></div></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="termination.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="std_contents.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="concept_checking.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Termination </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Concept Checking</td></tr></table></div></body></html>
\ No newline at end of file
+ </pre></div></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="termination.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="std_contents.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="errno.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Termination </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Use of errno by the library</td></tr></table></div></body></html>
\ No newline at end of file
</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types">Types</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types.fundamental">Fundamental Types</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.numeric_limits">Numeric Properties</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.null">NULL</a></span></dt></dl></dd><dt><span class="section"><a href="dynamic_memory.html">Dynamic Memory</a></span></dt><dt><span class="section"><a href="termination.html">Termination</a></span></dt><dd><dl><dt><span class="section"><a href="termination.html#support.termination.handlers">Termination Handlers</a></span></dt><dt><span class="section"><a href="termination.html#support.termination.verbose">Verbose Terminate Handler</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="diagnostics.html">5.
Diagnostics
-</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions">Exceptions</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.api">API Reference</a></span></dt><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.data">Adding Data to <code class="classname">exception</code></a></span></dt></dl></dd><dt><span class="section"><a href="concept_checking.html">Concept Checking</a></span></dt></dl></dd><dt><span class="chapter"><a href="utilities.html">6.
+</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions">Exceptions</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.api">API Reference</a></span></dt><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.data">Adding Data to <code class="classname">exception</code></a></span></dt></dl></dd><dt><span class="section"><a href="
errno.html">Use of errno by the library</a></span></dt><dt><span class="section"><a href="concept_checking.html">Concept Checking</a></span></dt></dl></dd><dt><span class="chapter"><a href="utilities.html">6.
Utilities
</a></span></dt><dd><dl><dt><span class="section"><a href="utilities.html#std.util.functors">Functors</a></span></dt><dt><span class="section"><a href="pairs.html">Pairs</a></span></dt><dt><span class="section"><a href="memory.html">Memory</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#std.util.memory.allocator">Allocators</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#allocator.req">Requirements</a></span></dt><dt><span class="section"><a href="memory.html#allocator.design_issues">Design Issues</a></span></dt><dt><span class="section"><a href="memory.html#allocator.impl">Implementation</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#allocator.interface">Interface Design</a></span></dt><dt><span class="section"><a href="memory.html#allocator.default">Selecting Default Allocation Policy</a></span></dt><dt><span class="section"><a href="memory.html#allocator.caching">Disabling Memory Caching</a></span></dt></dl></dd><dt><span class="section"><a href="memory.html#allocator.using">Using a Specific Allocator</a></span></dt><dt><span class="section"><a href="memory.html#allocator.custom">Custom Allocators</a></span></dt><dt><span class="section"><a href="memory.html#allocator.ext">Extension Allocators</a></span></dt></dl></dd><dt><span class="section"><a href="memory.html#std.util.memory.auto_ptr">auto_ptr</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#auto_ptr.limitations">Limitations</a></span></dt><dt><span class="section"><a href="memory.html#auto_ptr.using">Use in Containers</a></span></dt></dl></dd><dt><span class="section"><a href="memory.html#std.util.memory.shared_ptr">shared_ptr</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#shared_ptr.req">Requirements</a></span></dt><dt><span class="section"><a href="memory.html#shared_ptr.design_issues">Design Issues</a></span></dt><dt><span class="section"><a href="memory.html#shared_ptr.impl">Implementation</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#shared_ptr.hier">Class Hierarchy</a></span></dt><dt><span class="section"><a href="memory.html#shared_ptr.thread">Thread Safety</a></span></dt><dt><span class="section"><a href="memory.html#shared_ptr.policy">Selecting Lock Policy</a></span></dt><dt><span class="section"><a href="memory.html#shared_ptr.rel">Related functions and classes</a></span></dt></dl></dd><dt><span class="section"><a href="memory.html#shared_ptr.using">Use</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#shared_ptr.examples">Examples</a></span></dt><dt><span class="section"><a href="memory.html#shared_ptr.issues">Unresolved Issues</a></span></dt></dl></dd><dt><span class="section"><a href="memory.html#shared_ptr.ack">Acknowledgments</a></span></dt></dl></dd></dl></dd><dt><span class="section"><a href="traits.html">Traits</a></span></dt></dl></dd><dt><span class="chapter"><a href="strings.html">7.
</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types">Types</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types.fundamental">Fundamental Types</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.numeric_limits">Numeric Properties</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.null">NULL</a></span></dt></dl></dd><dt><span class="section"><a href="dynamic_memory.html">Dynamic Memory</a></span></dt><dt><span class="section"><a href="termination.html">Termination</a></span></dt><dd><dl><dt><span class="section"><a href="termination.html#support.termination.handlers">Termination Handlers</a></span></dt><dt><span class="section"><a href="termination.html#support.termination.verbose">Verbose Terminate Handler</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="diagnostics.html">5.
Diagnostics
-</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions">Exceptions</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.api">API Reference</a></span></dt><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.data">Adding Data to <code class="classname">exception</code></a></span></dt></dl></dd><dt><span class="section"><a href="concept_checking.html">Concept Checking</a></span></dt></dl></dd><dt><span class="chapter"><a href="utilities.html">6.
+</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions">Exceptions</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.api">API Reference</a></span></dt><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.data">Adding Data to <code class="classname">exception</code></a></span></dt></dl></dd><dt><span class="section"><a href="
errno.html">Use of errno by the library</a></span></dt><dt><span class="section"><a href="concept_checking.html">Concept Checking</a></span></dt></dl></dd><dt><span class="chapter"><a href="utilities.html">6.
Utilities
</a></span></dt><dd><dl><dt><span class="section"><a href="utilities.html#std.util.functors">Functors</a></span></dt><dt><span class="section"><a href="pairs.html">Pairs</a></span></dt><dt><span class="section"><a href="memory.html">Memory</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#std.util.memory.allocator">Allocators</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#allocator.req">Requirements</a></span></dt><dt><span class="section"><a href="memory.html#allocator.design_issues">Design Issues</a></span></dt><dt><span class="section"><a href="memory.html#allocator.impl">Implementation</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#allocator.interface">Interface Design</a></span></dt><dt><span class="section"><a href="memory.html#allocator.default">Selecting Default Allocation Policy</a></span></dt><dt><span class="section"><a href="memory.html#allocator.caching">Disabling Memory Caching</a></span></dt></dl></dd><dt><span class="section"><a href="memory.html#allocator.using">Using a Specific Allocator</a></span></dt><dt><span class="section"><a href="memory.html#allocator.custom">Custom Allocators</a></span></dt><dt><span class="section"><a href="memory.html#allocator.ext">Extension Allocators</a></span></dt></dl></dd><dt><span class="section"><a href="memory.html#std.util.memory.auto_ptr">auto_ptr</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#auto_ptr.limitations">Limitations</a></span></dt><dt><span class="section"><a href="memory.html#auto_ptr.using">Use in Containers</a></span></dt></dl></dd><dt><span class="section"><a href="memory.html#std.util.memory.shared_ptr">shared_ptr</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#shared_ptr.req">Requirements</a></span></dt><dt><span class="section"><a href="memory.html#shared_ptr.design_issues">Design Issues</a></span></dt><dt><span class="section"><a href="memory.html#shared_ptr.impl">Implementation</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#shared_ptr.hier">Class Hierarchy</a></span></dt><dt><span class="section"><a href="memory.html#shared_ptr.thread">Thread Safety</a></span></dt><dt><span class="section"><a href="memory.html#shared_ptr.policy">Selecting Lock Policy</a></span></dt><dt><span class="section"><a href="memory.html#shared_ptr.rel">Related functions and classes</a></span></dt></dl></dd><dt><span class="section"><a href="memory.html#shared_ptr.using">Use</a></span></dt><dd><dl><dt><span class="section"><a href="memory.html#shared_ptr.examples">Examples</a></span></dt><dt><span class="section"><a href="memory.html#shared_ptr.issues">Unresolved Issues</a></span></dt></dl></dd><dt><span class="section"><a href="memory.html#shared_ptr.ack">Acknowledgments</a></span></dt></dl></dd></dl></dd><dt><span class="section"><a href="traits.html">Traits</a></span></dt></dl></dd><dt><span class="chapter"><a href="strings.html">7.
</section>
</section>
+<section xml:id="std.diagnostics.errno" xreflabel="errno"><info><title>Use of errno by the library</title></info>
+ <?dbhtml filename="errno.html"?>
+
+ <para>
+ The C and POSIX standards guarantee that <varname>errno</varname>
+ is never set to zero by any library function.
+ The C++ standard has less to say about when <varname>errno</varname>
+ is or isn't set, but libstdc++ follows the same rule and never sets
+ it to zero.
+ </para>
+
+ <para>
+ On the other hand, there are few guarantees about when the C++ library
+ sets <varname>errno</varname> on error, beyond what is specified for
+ functions that come from the C library.
+ For example, when <function>std::stoi</function> throws an exception of
+ type <classname>std::out_of_range</classname>, <varname>errno</varname>
+ may or may not have been set to <constant>ERANGE</constant>.
+ </para>
+
+ <para>
+ Parts of the C++ library may be implemented in terms of C library
+ functions, which may result in <varname>errno</varname> being set
+ with no explicit call to a C function. For example, on a target where
+ <function>operator new</function> uses <function>malloc</function>
+ a failed memory allocation with <function>operator new</function> might
+ set <varname>errno</varname> to <constant>ENOMEM</constant>.
+ Which C++ library functions can set <varname>errno</varname> in this way
+ is unspecified because it may vary between platforms and between releases.
+ </para>
+
+</section>
+
<section xml:id="std.diagnostics.concept_checking" xreflabel="Concept Checking"><info><title>Concept Checking</title></info>
<?dbhtml filename="concept_checking.html"?>
_Ret __ret;
_CharT* __endptr;
- const int __saved_errno = errno;
- errno = 0;
+
+ struct _Save_errno {
+ _Save_errno() : _M_errno(errno) { errno = 0; }
+ ~_Save_errno() { if (errno == 0) errno = _M_errno; }
+ int _M_errno;
+ } const __save_errno;
+
const _TRet __tmp = __convf(__str, &__endptr, __base...);
if (__endptr == __str)
std::__throw_out_of_range(__name);
else
__ret = __tmp;
- errno = __saved_errno;
if (__idx)
*__idx = __endptr - __str;
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