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<html><head><meta http-equiv="X-UA-Compatible" content="IE=edge" /><link rel="shortcut icon" href="../icons/favicon.ico" /><link rel="stylesheet" type="text/css" href="../styles/branding.css" /><link rel="stylesheet" type="text/css" href="../styles/branding-en-US.css" /><script type="text/javascript" src="../scripts/branding.js"> </script><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>gmp_lib.mpf_get_str Method (char_ptr, ptr(mp_exp_t), Int32, size_t, mpf_t)</title><meta name="Language" content="en-us" /><meta name="Microsoft.Help.Id" content="M:Math.Gmp.Native.gmp_lib.mpf_get_str(Math.Gmp.Native.char_ptr,Math.Gmp.Native.ptr{Math.Gmp.Native.mp_exp_t},System.Int32,Math.Gmp.Native.size_t,Math.Gmp.Native.mpf_t)" /><meta name="Description" content="Convert to a string of digits in base ." /><meta name="Microsoft.Help.ContentType" content="Reference" /><meta name="BrandingAware" content="true" /><meta name="container" content="Math.Gmp.Native" /><meta name="file" content="bad56282-fbca-6e3b-03c8-085cff07eed8" /><meta name="guid" content="bad56282-fbca-6e3b-03c8-085cff07eed8" /><link type="text/css" rel="stylesheet" href="../styles/highlight.css" /><script type="text/javascript" src="../scripts/highlight.js"> </script><link rel="stylesheet" type="text/css" href="../styles/branding-Website.css" /><script type="text/javascript" src="../scripts/jquery-1.11.0.min.js"></script><script type="text/javascript" src="../scripts/branding-Website.js"></script><script type="text/javascript" src="../scripts/clipboard.min.js"></script></head><body onload="OnLoad('cs')"><input type="hidden" id="userDataCache" class="userDataStyle" /><div class="pageHeader" id="PageHeader">GMP Native Interface for .NET<form id="SearchForm" method="get" action="#" onsubmit="javascript:TransferToSearchPage(); return false;"><input id="SearchTextBox" type="text" maxlength="200" /><button id="SearchButton" type="submit"></button></form></div><div class="pageBody"><div class="leftNav" id="leftNav"><div id="tocNav"><div class="toclevel0" data-toclevel="0"><a class="tocCollapsed" onclick="javascript: Toggle(this);" href="#!" /><a data-tochassubtree="true" href="846f5c8a-6cba-433e-9f18-cde2ff5695cd.htm" title="GMP Native Interface for .NET" tocid="roottoc">GMP Native Interface for .NET</a></div><div class="toclevel0" data-toclevel="0"><a class="tocCollapsed" onclick="javascript: Toggle(this);" href="#!" /><a data-tochassubtree="true" href="d9c51b9f-0c54-770b-28ea-6eebd8fef368.htm" title="Math.Gmp.Native" tocid="d9c51b9f-0c54-770b-28ea-6eebd8fef368">Math.Gmp.Native</a></div><div class="toclevel0" data-toclevel="0"><a class="tocCollapsed" onclick="javascript: Toggle(this);" href="#!" /><a data-tochassubtree="true" href="3af6b34c-3242-2b75-e7c7-ab79af8a4b0f.htm" title="gmp_lib Class" tocid="3af6b34c-3242-2b75-e7c7-ab79af8a4b0f">gmp_lib Class</a></div><div class="toclevel0" data-toclevel="0"><a class="tocCollapsed" onclick="javascript: Toggle(this);" href="#!" /><a data-tochassubtree="true" href="0fa7cbf3-e8f4-6b14-d829-8aa663e77c74.htm" title="gmp_lib Methods" tocid="0fa7cbf3-e8f4-6b14-d829-8aa663e77c74">gmp_lib Methods</a></div><div class="toclevel1" data-toclevel="1" data-childrenloaded="true"><a class="tocExpanded" onclick="javascript: Toggle(this);" href="#!" /><a data-tochassubtree="true" href="73766ead-a037-a852-4589-04adc3407e15.htm" title="mpf_get_str Method " tocid="73766ead-a037-a852-4589-04adc3407e15">mpf_get_str Method </a></div><div class="toclevel2" data-toclevel="2"><a data-tochassubtree="false" href="9e7b9239-a7a8-4667-f6c7-bfc142d3f429.htm" title="mpf_get_str Method (char_ptr, mp_exp_t, Int32, size_t, mpf_t)" tocid="9e7b9239-a7a8-4667-f6c7-bfc142d3f429">mpf_get_str Method (char_ptr, mp_exp_t, Int32, size_t, mpf_t)</a></div><div class="toclevel2 current" data-toclevel="2"><a data-tochassubtree="false" href="bad56282-fbca-6e3b-03c8-085cff07eed8.htm" title="mpf_get_str Method (char_ptr, ptr(mp_exp_t), Int32, size_t, mpf_t)" tocid="bad56282-fbca-6e3b-03c8-085cff07eed8">mpf_get_str Method (char_ptr, ptr(mp_exp_t), Int32, size_
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Convert <span class="parameter">op</span> to a string of digits in base <span class="parameter">base</span>.
</div><p> </p>
<strong>Namespace:</strong>
 <a href="d9c51b9f-0c54-770b-28ea-6eebd8fef368.htm">Math.Gmp.Native</a><br />
<strong>Assembly:</strong>
 Math.Gmp.Native (in Math.Gmp.Native.dll) Version: 1.0.0.0 (1.0.0.0)<div class="collapsibleAreaRegion"><span class="collapsibleRegionTitle" onclick="SectionExpandCollapse('ID1RB')" onkeypress="SectionExpandCollapse_CheckKey('ID1RB', event)" tabindex="0"><img id="ID1RBToggle" class="collapseToggle" src="../icons/SectionExpanded.png" />Syntax</span></div><div id="ID1RBSection" class="collapsibleSection"><div class="codeSnippetContainer"><div class="codeSnippetContainerTabs"><div id="ID0EDCA_tab1" class="codeSnippetContainerTab"><a href="#" onclick="javascript:ChangeTab('ID0EDCA','cs','1','4');return false;">C#</a></div><div id="ID0EDCA_tab2" class="codeSnippetContainerTab"><a href="#" onclick="javascript:ChangeTab('ID0EDCA','vb','2','4');return false;">VB</a></div><div id="ID0EDCA_tab3" class="codeSnippetContainerTab"><a href="#" onclick="javascript:ChangeTab('ID0EDCA','cpp','3','4');return false;">C++</a></div><div id="ID0EDCA_tab4" class="codeSnippetContainerTab"><a href="#" onclick="javascript:ChangeTab('ID0EDCA','fs','4','4');return false;">F#</a></div></div><div class="codeSnippetContainerCodeContainer"><div class="codeSnippetToolBar"><div class="codeSnippetToolBarText"><a id="ID0EDCA_copyCode" href="#" class="copyCodeSnippet" onclick="javascript:CopyToClipboard('ID0EDCA');return false;" title="Copy">Copy</a></div></div><div id="ID0EDCA_code_Div1" class="codeSnippetContainerCode" style="display: block"><pre xml:space="preserve"><span class="keyword">public</span> <span class="keyword">static</span> <span class="identifier">char_ptr</span> <span class="identifier">mpf_get_str</span>(
<span class="identifier">char_ptr</span> <span class="parameter">str</span>,
<span class="identifier">ptr</span>&lt;<span class="identifier">mp_exp_t</span>&gt; <span class="parameter">expptr</span>,
<span class="identifier">int</span> <span class="parameter">base</span>,
<span class="identifier">size_t</span> <span class="parameter">n_digits</span>,
<span class="identifier">mpf_t</span> <span class="parameter">op</span>
)</pre></div><div id="ID0EDCA_code_Div2" class="codeSnippetContainerCode" style="display: none"><pre xml:space="preserve"><span class="keyword">Public</span> <span class="keyword">Shared</span> <span class="keyword">Function</span> <span class="identifier">mpf_get_str</span> (
<span class="parameter">str</span> <span class="keyword">As</span> <span class="identifier">char_ptr</span>,
<span class="parameter">expptr</span> <span class="keyword">As</span> <span class="identifier">ptr</span>(<span class="keyword">Of</span> <span class="identifier">mp_exp_t</span>),
<span class="parameter">base</span> <span class="keyword">As</span> <span class="identifier">Integer</span>,
<span class="parameter">n_digits</span> <span class="keyword">As</span> <span class="identifier">size_t</span>,
<span class="parameter">op</span> <span class="keyword">As</span> <span class="identifier">mpf_t</span>
) <span class="keyword">As</span> <span class="identifier">char_ptr</span></pre></div><div id="ID0EDCA_code_Div3" class="codeSnippetContainerCode" style="display: none"><pre xml:space="preserve"><span class="keyword">public</span>:
<span class="keyword">static</span> <span class="identifier">char_ptr</span> <span class="identifier">mpf_get_str</span>(
<span class="identifier">char_ptr</span> <span class="parameter">str</span>,
<span class="identifier">ptr</span>&lt;<span class="identifier">mp_exp_t</span>&gt;^ <span class="parameter">expptr</span>,
<span class="identifier">int</span> <span class="parameter">base</span>,
<span class="identifier">size_t</span> <span class="parameter">n_digits</span>,
<span class="identifier">mpf_t</span>^ <span class="parameter">op</span>
)</pre></div><div id="ID0EDCA_code_Div4" class="codeSnippetContainerCode" style="display: none"><pre xml:space="preserve"><span class="keyword">static</span> <span class="keyword">member</span> <span class="identifier">mpf_get_str</span> :
<span class="parameter">str</span> : <span class="identifier">char_ptr</span> *
<span class="parameter">expptr</span> : <span class="identifier">ptr</span>&lt;<span class="identifier">mp_exp_t</span>&gt; *
<span class="parameter">base</span> : <span class="identifier">int</span> *
<span class="parameter">n_digits</span> : <span class="identifier">size_t</span> *
<span class="parameter">op</span> : <span class="identifier">mpf_t</span> <span class="keyword">-&gt;</span> <span class="identifier">char_ptr</span>
</pre></div></div></div><script type="text/javascript">AddLanguageTabSet("ID0EDCA");</script><h4 class="subHeading">Parameters</h4><dl><dt><span class="parameter">str</span></dt><dd>Type: <a href="06249483-9daf-95f9-32c7-30195550bbcc.htm">Math.Gmp.Native<span id="LST793D64A7_3"></span><script type="text/javascript">AddLanguageSpecificTextSet("LST793D64A7_3?cs=.|vb=.|cpp=::|nu=.|fs=.");</script>char_ptr</a><br />The output string.</dd><dt><span class="parameter">expptr</span></dt><dd>Type: <a href="542faa00-d28a-72a2-2dd8-6c6021e683ce.htm">Math.Gmp.Native<span id="LST793D64A7_4"></span><script type="text/javascript">AddLanguageSpecificTextSet("LST793D64A7_4?cs=.|vb=.|cpp=::|nu=.|fs=.");</script>ptr</a><span id="LST793D64A7_5"></span><script type="text/javascript">AddLanguageSpecificTextSet("LST793D64A7_5?cs=&lt;|vb=(Of |cpp=&lt;|fs=&lt;'|nu=(");</script><a href="e6a17880-791f-37d4-4942-cf26ce7d4cbf.htm">mp_exp_t</a><span id="LST793D64A7_6"></span><script type="text/javascript">AddLanguageSpecificTextSet("LST793D64A7_6?cs=&gt;|vb=)|cpp=&gt;|fs=&gt;|nu=)");</script><br />The exponent.</dd><dt><span class="parameter">base</span></dt><dd>Type: <a href="http://msdn2.microsoft.com/en-us/library/td2s409d" target="_blank">System<span id="LST793D64A7_7"></span><script type="text/javascript">AddLanguageSpecificTextSet("LST793D64A7_7?cs=.|vb=.|cpp=::|nu=.|fs=.");</script>Int32</a><br />The base.</dd><dt><span class="parameter">n_digits</span></dt><dd>Type: <a href="d9761bfb-1882-59d2-e89b-c6460141f9a6.htm">Math.Gmp.Native<span id="LST793D64A7_8"></span><script type="text/javascript">AddLanguageSpecificTextSet("LST793D64A7_8?cs=.|vb=.|cpp=::|nu=.|fs=.");</script>size_t</a><br />Maximum number of output digits.</dd><dt><span class="parameter">op</span></dt><dd>Type: <a href="37c88d6c-8d02-2330-ad77-f20fb73d1677.htm">Math.Gmp.Native<span id="LST793D64A7_9"></span><script type="text/javascript">AddLanguageSpecificTextSet("LST793D64A7_9?cs=.|vb=.|cpp=::|nu=.|fs=.");</script>mpf_t</a><br />The operand floating-point number.</dd></dl><h4 class="subHeading">Return Value</h4>Type: <a href="06249483-9daf-95f9-32c7-30195550bbcc.htm">char_ptr</a><br />A pointer to the result string is returned, being either the allocated block or the given <span class="parameter">str</span>.</div><div class="collapsibleAreaRegion"><span class="collapsibleRegionTitle" onclick="SectionExpandCollapse('ID2RB')" onkeypress="SectionExpandCollapse_CheckKey('ID2RB', event)" tabindex="0"><img id="ID2RBToggle" class="collapseToggle" src="../icons/SectionExpanded.png" />Remarks</span></div><div id="ID2RBSection" class="collapsibleSection"><p>
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The <span class="parameter">base</span> argument may vary from 2 to 62 or from -2 to -36.
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Up to <span class="parameter">n_digits</span> digits will be generated.
Trailing zeros are not returned.
No more digits than can be accurately represented by <span class="parameter">op</span> are ever generated.
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If <span class="parameter">n_digits</span> is 0 then that accurate maximum number of digits are generated.
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</p><p>
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For <span class="parameter">base</span> in the range 2..36, digits and lower-case letters are used; for -2..-36,
digits and upper-case letters are used; for 37..62, digits, upper-case letters, and lower-case letters
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(in that significance order) are used.
</p><p>
If <span class="parameter">str</span> is NULL, the result string is allocated using the current allocation function
(see <a href="https://gmplib.org/manual/Custom-Allocation.html#Custom-Allocation">GNU MP - Custom Allocation</a>).
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The block will be strlen(str) + 1 bytes, that being exactly enough for the string and null-terminator.
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</p><p>
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If <span class="parameter">str</span> is not NULL, it should point to a block of <span class="parameter">n_digits</span> + 2 bytes,
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that being enough for the mantissa, a possible minus sign, and a null-terminator.
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When <span class="parameter">n_digits</span> is 0 to get all significant digits, an application wont be able to know
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the space required, and <span class="parameter">str</span> should be NULL in that case.
</p><p>
The generated string is a fraction, with an implicit radix point immediately to the left of the first digit.
The applicable exponent is written through the <span class="parameter">expptr</span> pointer.
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For example, the number 3.1416 would be returned as string "31416" and exponent 1.
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</p><p>
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When <span class="parameter">op</span> is zero, an empty string is produced and the exponent returned is 0.
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</p></div><div class="collapsibleAreaRegion"><span class="collapsibleRegionTitle" onclick="SectionExpandCollapse('ID3RB')" onkeypress="SectionExpandCollapse_CheckKey('ID3RB', event)" tabindex="0"><img id="ID3RBToggle" class="collapseToggle" src="../icons/SectionExpanded.png" />Examples</span></div><div id="ID3RBSection" class="collapsibleSection"><div class="codeSnippetContainer"><div class="codeSnippetContainerTabs"><div id="ID0EDAABA_tab1" class="codeSnippetContainerTab"><a href="#" onclick="javascript:ChangeTab('ID0EDAABA','cs','1','4');return false;">C#</a></div><div id="ID0EDAABA_tab2" class="codeSnippetContainerTab"><a href="#" onclick="javascript:ChangeTab('ID0EDAABA','vb','2','4');return false;">VB</a></div><div id="ID0EDAABA_tab3" class="codeSnippetContainerTabPhantom"><a href="#" onclick="javascript:ChangeTab('ID0EDAABA','cpp','3','4');return false;">C++</a></div><div id="ID0EDAABA_tab4" class="codeSnippetContainerTabPhantom"><a href="#" onclick="javascript:ChangeTab('ID0EDAABA','fs','4','4');return false;">F#</a></div></div><div class="codeSnippetContainerCodeContainer"><div class="codeSnippetToolBar"><div class="codeSnippetToolBarText"><a id="ID0EDAABA_copyCode" href="#" class="copyCodeSnippet" onclick="javascript:CopyToClipboard('ID0EDAABA');return false;" title="Copy">Copy</a></div></div><div id="ID0EDAABA_code_Div1" class="codeSnippetContainerCode" style="display: block"><pre xml:space="preserve"><span class="highlight-comment">// Set default precision to 64 bits.</span>
gmp_lib.mpf_set_default_prec(<span class="highlight-number">64</span>U);
<span class="highlight-comment">// Create, initialize, and set a new floating-point number to -8.0</span>
mpf_t x = <span class="highlight-keyword">new</span> mpf_t();
gmp_lib.mpf_init_set_d(x, <span class="highlight-number">-8.0</span>);
<span class="highlight-comment">// Assert that the value of x is -8.</span>
ptr&lt;mp_exp_t&gt; exp = <span class="highlight-keyword">new</span> ptr&lt;mp_exp_t&gt;(<span class="highlight-number">0</span>);
char_ptr <span class="highlight-keyword">value</span> = gmp_lib.mpf_get_str(char_ptr.Zero, exp, <span class="highlight-number">10</span>, <span class="highlight-number">0</span>, x);
Assert.IsTrue(<span class="highlight-keyword">value</span>.ToString() == <span class="highlight-literal">"-8"</span>);
Assert.IsTrue(exp.Value == <span class="highlight-number">1</span>);
<span class="highlight-comment">// Release unmanaged memory allocated for x.</span>
gmp_lib.mpf_clear(x);
gmp_lib.free(<span class="highlight-keyword">value</span>);</pre></div><div id="ID0EDAABA_code_Div2" class="codeSnippetContainerCode" style="display: none"><pre xml:space="preserve"><span class="highlight-comment">' Set default precision to 64 bits.</span>
gmp_lib.mpf_set_default_prec(<span class="highlight-number">64</span>UI)
<span class="highlight-comment">' Create, initialize, and set a new floating-point number to -8.0</span>
<span class="highlight-keyword">Dim</span> x <span class="highlight-keyword">As</span> <span class="highlight-keyword">New</span> mpf_t()
gmp_lib.mpf_init_set_d(x, <span class="highlight-number">-8.0</span>)
<span class="highlight-comment">' Assert that the value of x is -8.</span>
<span class="highlight-keyword">Dim</span> exp <span class="highlight-keyword">As</span> <span class="highlight-keyword">New</span> ptr(<span class="highlight-keyword">Of</span> mp_exp_t)(<span class="highlight-number">0</span>)
<span class="highlight-keyword">Dim</span> value <span class="highlight-keyword">As</span> char_ptr = gmp_lib.mpf_get_str(char_ptr.Zero, exp, <span class="highlight-number">10</span>, <span class="highlight-number">0</span>, x)
Assert.IsTrue(value.ToString() = <span class="highlight-literal">"-8"</span>)
Assert.IsTrue(exp.Value = <span class="highlight-number">1</span>)
<span class="highlight-comment">' Release unmanaged memory allocated for x.</span>
gmp_lib.mpf_clear(x)
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gmp_lib.free(value)</pre></div><div id="ID0EDAABA_code_Div3" class="codeSnippetContainerCode" style="display: none"><p>No code example is currently available or this language may not be supported.</p></div><div id="ID0EDAABA_code_Div4" class="codeSnippetContainerCode" style="display: none"><p>No code example is currently available or this language may not be supported.</p></div></div></div><script type="text/javascript">AddLanguageTabSet("ID0EDAABA");</script></div><div class="collapsibleAreaRegion" id="seeAlsoSection"><span class="collapsibleRegionTitle" onclick="SectionExpandCollapse('ID4RB')" onkeypress="SectionExpandCollapse_CheckKey('ID4RB', event)" tabindex="0"><img id="ID4RBToggle" class="collapseToggle" src="../icons/SectionExpanded.png" />See Also</span></div><div id="ID4RBSection" class="collapsibleSection"><h4 class="subHeading">Reference</h4><div class="seeAlsoStyle"><a href="3af6b34c-3242-2b75-e7c7-ab79af8a4b0f.htm">gmp_lib Class</a></div><div class="seeAlsoStyle"><a href="73766ead-a037-a852-4589-04adc3407e15.htm">mpf_get_str Overload</a></div><div class="seeAlsoStyle"><a href="d9c51b9f-0c54-770b-28ea-6eebd8fef368.htm">Math.Gmp.Native Namespace</a></div><div class="seeAlsoStyle"><a href="648fa405-45d3-506a-f6be-72642e8a7f32.htm">mpf_get_d</a></div><div class="seeAlsoStyle"><a href="e1edc21e-74a0-b44c-216b-bad204b5a48a.htm">mpf_get_d_2exp</a></div><div class="seeAlsoStyle"><a href="d948e832-ee71-628a-6a7b-766138afff62.htm">mpf_get_si</a></div><div class="seeAlsoStyle"><a href="aa3fd0ea-a8b6-674b-59ff-b6d4785baed1.htm">mpf_get_ui</a></div><div class="seeAlsoStyle"><a href="3af6b34c-3242-2b75-e7c7-ab79af8a4b0f.htm"><a href="/Math.Gmp.Native/html/3af6b34c-3242-2b75-e7c7-ab79af8a4b0f.htm#Converting_Floats">Converting Floats</a></a></div><div class="seeAlsoStyle"><a href="3af6b34c-3242-2b75-e7c7-ab79af8a4b0f.htm"><a href="https://gmplib.org/manual/Converting-Floats.html#Converting-Floats">GNU MP - Converting Floats</a></a></div></div></div></div><div id="pageFooter" class="pageFooter"> </div></body></html>