summaryrefslogtreecommitdiff
path: root/devdocs/c/string%2Fbyte%2Fstrlen.html
diff options
context:
space:
mode:
authorCraig Jennings <c@cjennings.net>2024-04-07 13:41:34 -0500
committerCraig Jennings <c@cjennings.net>2024-04-07 13:41:34 -0500
commit754bbf7a25a8dda49b5d08ef0d0443bbf5af0e36 (patch)
treef1190704f78f04a2b0b4c977d20fe96a828377f1 /devdocs/c/string%2Fbyte%2Fstrlen.html
new repository
Diffstat (limited to 'devdocs/c/string%2Fbyte%2Fstrlen.html')
-rw-r--r--devdocs/c/string%2Fbyte%2Fstrlen.html49
1 files changed, 49 insertions, 0 deletions
diff --git a/devdocs/c/string%2Fbyte%2Fstrlen.html b/devdocs/c/string%2Fbyte%2Fstrlen.html
new file mode 100644
index 00000000..e8a60fbc
--- /dev/null
+++ b/devdocs/c/string%2Fbyte%2Fstrlen.html
@@ -0,0 +1,49 @@
+ <h1 id="firstHeading" class="firstHeading">strlen, strnlen_s</h1> <table class="t-dcl-begin"> <tr class="t-dsc-header"> <th> Defined in header <code>&lt;string.h&gt;</code> </th> <th> </th> <th> </th> </tr> <tr class="t-dcl"> <td> <pre data-language="c">size_t strlen( const char *str );</pre>
+</td> <td> (1) </td> <td class="t-dcl-nopad"> </td> </tr> <tr class="t-dcl t-since-c11"> <td> <pre data-language="c">size_t strnlen_s( const char *str, size_t strsz );</pre>
+</td> <td> (2) </td> <td> <span class="t-mark-rev t-since-c11">(since C11)</span> </td> </tr> </table> <div class="t-li1">
+<span class="t-li">1)</span> Returns the length of the given null-terminated byte string, that is, the number of characters in a character array whose first element is pointed to by <code>str</code> up to and not including the first null character.</div> <div class="t-li1">
+ The behavior is undefined if <code>str</code> is not a pointer to a null-terminated byte string.</div> <div class="t-li1">
+<span class="t-li">2)</span> Same as <span class="t-v">(1)</span>, except that the function returns zero if <code>str</code> is a null pointer and returns <code>strsz</code> if the null character was not found in the first <code>strsz</code> bytes of <code>str</code>.</div> <div class="t-li1">
+ The behavior is undefined if both <code>str</code> points to a character array which lacks the null character and the size of that character array &lt; <code>strsz</code>; in other words, an erroneous value of <code>strsz</code> does not expose the impending buffer overflow. As with all bounds-checked functions, <code>strnlen_s</code> only guaranteed to be available if <code>__STDC_LIB_EXT1__</code> is defined by the implementation and if the user defines <code>__STDC_WANT_LIB_EXT1__</code> to the integer constant <code>1</code> before including <a href="../byte" title="c/string/byte"><code>&lt;string.h&gt;</code></a>.</div> <h3 id="Parameters"> Parameters</h3> <table class="t-par-begin"> <tr class="t-par"> <td> str </td> <td> - </td> <td> pointer to the null-terminated byte string to be examined </td>
+</tr> <tr class="t-par"> <td> strsz </td> <td> - </td> <td> maximum number of characters to examine </td>
+</tr>
+</table> <h3 id="Return_value"> Return value</h3> <div class="t-li1">
+<span class="t-li">1)</span> The length of the null-terminated byte string <code>str</code>.</div> <div class="t-li1">
+<span class="t-li">2)</span> The length of the null-terminated byte string <code>str</code> on success, zero if <code>str</code> is a null pointer, <code>strsz</code> if the null character was not found.</div> <h3 id="Notes"> Notes</h3> <p><code>strnlen_s</code> and <code>wcsnlen_s</code> are the only <a href="../../error" title="c/error">bounds-checked functions</a> that do not invoke the runtime constraints handler. They are pure utility functions used to provide limited support for non-null terminated strings.</p>
+<h3 id="Example"> Example</h3> <div class="t-example"> <div class="c source-c"><pre data-language="c">#define __STDC_WANT_LIB_EXT1__ 1
+#include &lt;string.h&gt;
+#include &lt;stdio.h&gt;
+
+int main(void)
+{
+ const char str[] = "How many characters does this string contain?";
+
+ printf("without null character: %zu\n", strlen(str));
+ printf("with null character: %zu\n", sizeof str);
+
+#ifdef __STDC_LIB_EXT1__
+ printf("without null character: %zu\n", strnlen_s(str, sizeof str));
+#endif
+}</pre></div> <p>Possible output:</p>
+<div class="text source-text"><pre data-language="c">without null character: 45
+with null character: 46
+without null character: 45</pre></div> </div> <h3 id="References"> References</h3> <ul>
+<li> C11 standard (ISO/IEC 9899:2011): </li>
+<ul>
+<li> 7.24.6.3 The strlen function (p: 372) </li>
+<li> K.3.7.4.4 The strnlen_s function (p: 623) </li>
+</ul>
+<li> C99 standard (ISO/IEC 9899:1999): </li>
+<ul><li> 7.21.6.3 The strlen function (p: 334) </li></ul>
+<li> C89/C90 standard (ISO/IEC 9899:1990): </li>
+<ul><li> 4.11.6.3 The strlen function </li></ul>
+</ul> <h3 id="See_also"> See also</h3> <table class="t-dsc-begin"> <tr class="t-dsc"> <td> <div><a href="../wide/wcslen" title="c/string/wide/wcslen"> <span class="t-lines"><span>wcslen</span><span>wcsnlen_s</span></span></a></div>
+<div><span class="t-lines"><span><span class="t-mark-rev t-since-c95">(C95)</span></span><span><span class="t-mark-rev t-since-c11">(C11)</span></span></span></div> </td> <td> returns the length of a wide string <br> <span class="t-mark">(function)</span> </td>
+</tr> <tr class="t-dsc"> <td> <div><a href="../multibyte/mblen" title="c/string/multibyte/mblen"> <span class="t-lines"><span>mblen</span></span></a></div> </td> <td> returns the number of bytes in the next multibyte character <br> <span class="t-mark">(function)</span> </td>
+</tr> <tr class="t-dsc"> <td colspan="2"> <span><a href="https://en.cppreference.com/w/cpp/string/byte/strlen" title="cpp/string/byte/strlen">C++ documentation</a></span> for <code>strlen</code> </td>
+</tr> </table> <div class="_attribution">
+ <p class="_attribution-p">
+ &copy; cppreference.com<br>Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.<br>
+ <a href="https://en.cppreference.com/w/c/string/byte/strlen" class="_attribution-link">https://en.cppreference.com/w/c/string/byte/strlen</a>
+ </p>
+</div>