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diff --git a/share/doc/gfortran/Thread_002dsafety-of-the-runtime-library.html b/share/doc/gfortran/Thread_002dsafety-of-the-runtime-library.html new file mode 100644 index 0000000..86361c8 --- /dev/null +++ b/share/doc/gfortran/Thread_002dsafety-of-the-runtime-library.html @@ -0,0 +1,132 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1999-2023 Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 or +any later version published by the Free Software Foundation; with the +Invariant Sections being "Funding Free Software", the Front-Cover +Texts being (a) (see below), and with the Back-Cover Texts being (b) +(see below). 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Copies published by the Free Software Foundation raise + funds for GNU development. --> +<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>The GNU Fortran Compiler: Thread-safety of the runtime library</title> + +<meta name="description" content="The GNU Fortran Compiler: Thread-safety of the runtime library"> +<meta name="keywords" content="The GNU Fortran Compiler: Thread-safety of the runtime library"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> +<link href="index.html#Top" rel="start" title="Top"> +<link href="Option-Index.html#Option-Index" rel="index" title="Option Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="Compiler-Characteristics.html#Compiler-Characteristics" rel="up" title="Compiler Characteristics"> +<link href="Data-consistency-and-durability.html#Data-consistency-and-durability" rel="next" title="Data consistency and durability"> +<link href="MAX-and-MIN-intrinsics-with-REAL-NaN-arguments.html#MAX-and-MIN-intrinsics-with-REAL-NaN-arguments" rel="previous" title="MAX and MIN intrinsics with REAL NaN arguments"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.indentedblock {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smallindentedblock {margin-left: 3.2em; font-size: smaller} +div.smalllisp {margin-left: 3.2em} +kbd {font-style:oblique} +pre.display {font-family: inherit} +pre.format {font-family: inherit} +pre.menu-comment {font-family: serif} +pre.menu-preformatted {font-family: serif} +pre.smalldisplay {font-family: inherit; font-size: smaller} +pre.smallexample {font-size: smaller} +pre.smallformat {font-family: inherit; font-size: smaller} +pre.smalllisp {font-size: smaller} +span.nocodebreak {white-space:nowrap} +span.nolinebreak {white-space:nowrap} +span.roman {font-family:serif; font-weight:normal} +span.sansserif {font-family:sans-serif; font-weight:normal} +ul.no-bullet {list-style: none} +--> +</style> + + +</head> + +<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<a name="Thread_002dsafety-of-the-runtime-library"></a> +<div class="header"> +<p> +Next: <a href="Data-consistency-and-durability.html#Data-consistency-and-durability" accesskey="n" rel="next">Data consistency and durability</a>, Previous: <a href="MAX-and-MIN-intrinsics-with-REAL-NaN-arguments.html#MAX-and-MIN-intrinsics-with-REAL-NaN-arguments" accesskey="p" rel="previous">MAX and MIN intrinsics with REAL NaN arguments</a>, Up: <a href="Compiler-Characteristics.html#Compiler-Characteristics" accesskey="u" rel="up">Compiler Characteristics</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<a name="Thread_002dsafety-of-the-runtime-library-1"></a> +<h3 class="section">4.5 Thread-safety of the runtime library</h3> +<a name="index-thread_002dsafety_002c-threads"></a> + +<p>GNU Fortran can be used in programs with multiple threads, e.g. by +using OpenMP, by calling OS thread handling functions via the +<code>ISO_C_BINDING</code> facility, or by GNU Fortran compiled library code +being called from a multi-threaded program. +</p> +<p>The GNU Fortran runtime library, (<code>libgfortran</code>), supports being +called concurrently from multiple threads with the following +exceptions. +</p> +<p>During library initialization, the C <code>getenv</code> function is used, +which need not be thread-safe. Similarly, the <code>getenv</code> +function is used to implement the <code>GET_ENVIRONMENT_VARIABLE</code> and +<code>GETENV</code> intrinsics. It is the responsibility of the user to +ensure that the environment is not being updated concurrently when any +of these actions are taking place. +</p> +<p>The <code>EXECUTE_COMMAND_LINE</code> and <code>SYSTEM</code> intrinsics are +implemented with the <code>system</code> function, which need not be +thread-safe. It is the responsibility of the user to ensure that +<code>system</code> is not called concurrently. +</p> +<p>For platforms not supporting thread-safe POSIX functions, further +functionality might not be thread-safe. For details, please consult +the documentation for your operating system. +</p> +<p>The GNU Fortran runtime library uses various C library functions that +depend on the locale, such as <code>strtod</code> and <code>snprintf</code>. In +order to work correctly in locale-aware programs that set the locale +using <code>setlocale</code>, the locale is reset to the default “C” +locale while executing a formatted <code>READ</code> or <code>WRITE</code> +statement. On targets supporting the POSIX 2008 per-thread locale +functions (e.g. <code>newlocale</code>, <code>uselocale</code>, +<code>freelocale</code>), these are used and thus the global locale set +using <code>setlocale</code> or the per-thread locales in other threads are +not affected. However, on targets lacking this functionality, the +global LC_NUMERIC locale is set to “C” during the formatted I/O. +Thus, on such targets it’s not safe to call <code>setlocale</code> +concurrently from another thread while a Fortran formatted I/O +operation is in progress. Also, other threads doing something +dependent on the LC_NUMERIC locale might not work correctly if a +formatted I/O operation is in progress in another thread. +</p> +<hr> +<div class="header"> +<p> +Next: <a href="Data-consistency-and-durability.html#Data-consistency-and-durability" accesskey="n" rel="next">Data consistency and durability</a>, Previous: <a href="MAX-and-MIN-intrinsics-with-REAL-NaN-arguments.html#MAX-and-MIN-intrinsics-with-REAL-NaN-arguments" accesskey="p" rel="previous">MAX and MIN intrinsics with REAL NaN arguments</a>, Up: <a href="Compiler-Characteristics.html#Compiler-Characteristics" accesskey="u" rel="up">Compiler Characteristics</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |