blocks|key|920420|text|strtol为您提供了更大的灵活性，因为它实际上可以告诉您整个字符串是否已转换为整数。当无法将字符串转换为数字时(如在atol("help")中)，atol将返回0，这与atol("0")无法区分|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|920421|int+main()
{
++int+res_help+=+atol("help");
++int+res_zero+=+atol("0");

++printf("Got+from+help:+%25d,+from+zero:+%25d\n",+res_help,+res_zero);
++return+0;
}|code-block|syntax|javascript|920422|输出：|920423|Got+from+help:+0,+from+zero:+0|920424|strtol将使用其endptr参数指定转换失败的位置。|920425|int+main()
{
++char*+end;
++int+res_help+=+strtol("help",+&end,+10);

++if+(!*end)
++++printf("Converted+successfully\n");
++else
++++printf("Conversion+error,+non-convertible+part:+%25s",+end);

++return+0;
}|920426|920427|Conversion+error,+non-convertible+part:+help|920428|因此，对于任何严肃的编程，我绝对推荐使用strtol。它的使用有点棘手，但正如我在上面解释的那样，这有一个很好的理由。|920429|atol可能只适用于非常简单和可控的情况。|920430|entityMap^0|0|6|1N|C|22|4|2D|9|0|0|0|0|0|6|A|6|0|0|0|0|K|6|0|0|4|0^^$0|@$1|2|3|4|5|6|7|11|8|@$9|12|A|13|B|C]|$9|14|A|15|B|C]|$9|16|A|17|B|C]|$9|18|A|19|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|1A|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1B|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|1C|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1D|8|@$9|1E|A|1F|B|C]|$9|1G|A|1H|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|H|7|1I|8|@]|D|@]|E|$I|J]]|$1|S|3|L|5|6|7|1J|8|@]|D|@]|E|$]]|$1|T|3|U|5|H|7|1K|8|@]|D|@]|E|$I|J]]|$1|V|3|W|5|6|7|1L|8|@$9|1M|A|1N|B|C]]|D|@]|E|$]]|$1|X|3|Y|5|6|7|1O|8|@$9|1P|A|1Q|B|C]]|D|@]|E|$]]|$1|Z|3|-4|5|6|7|1R|8|@]|D|@]|E|$]]]|10|$]]

<code>strtol</code> provides you with more flexibility, as it can actually tell you if the whole string was converted to an integer or not. <code>atol</code>, when unable to convert the string to a number (like in <code>atol("help")</code>), returns 0, which is indistinguishable from <code>atol("0")</code>:

<pre><code>int main()
{
 int res_help = atol("help");
 int res_zero = atol("0");

 printf("Got from help: %d, from zero: %d\n", res_help, res_zero);
 return 0;
}
</code></pre>

Outputs:

<pre><code>Got from help: 0, from zero: 0
</code></pre>

<code>strtol</code> will specify, using its <code>endptr</code> argument, where the conversion failed.

<pre><code>int main()
{
 char* end;
 int res_help = strtol("help", &amp;end, 10);

 if (!*end)
 printf("Converted successfully\n");
 else
 printf("Conversion error, non-convertible part: %s", end);

 return 0;
}
</code></pre>

Outputs:

<pre><code>Conversion error, non-convertible part: help
</code></pre>

Therefore, for any serious programming, I definitely recommend using <code>strtol</code>. It's a bit more tricky to use but this has a good reason, as I explained above.

<code>atol</code> may be suitable only for very simple and controlled cases.

blocks|key|920542|text|atol(str)等同于|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|920543|strtol(str,+(char+**)NULL,+10);|code-block|syntax|javascript|920544|如果你想要结束指针(检查是否有更多的字符要读取，或者你实际上是否已经读取了任何字符)或者使用10以外的基数，那么使用strtol。否则，atol是可以的。|920545|entityMap^0|0|9|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

<code>atol(str)</code> is equivalent to

<pre><code>strtol(str, (char **)NULL, 10);
</code></pre>

Use strtol if you want the end pointer (to check whether there are more characters to read or if in fact you have read any at all) or a base other than 10. Otherwise, atol is fine.

blocks|key|1135152|text|如果内存有效，strtol()还有一个额外的好处，它可以将(可选)+endptr设置为指向无法转换的第一个字符。如果为NULL，它将被忽略。这样，如果您正在处理一个混合了数字和字符的字符串，您可以继续。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1135153|例如，|1135154|char+buf[]+=+"213982+and+the+rest";
char+*theRest;
long+int+num+=+strtol(buf,+&theRest,+10);
printf("%25ld\n",+num);++++/*+213982+*/
printf("%25s\n",+theRest);+/*+"+and+the+rest"+*/|code-block|syntax|javascript|1135155|entityMap^0|7|8|Y|6|1N|4|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|W|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

If memory serves, <code>strtol()</code> has the added benefit to set the (optional) <code>endptr</code> to point to the first character that could not be converted. If <code>NULL</code>, it is ignored. That way if you're processing a string containing numbers and characters mixed, you could continue.

e.g.,

<pre><code>char buf[] = "213982 and the rest";
char *theRest;
long int num = strtol(buf, &amp;theRest, 10);
printf("%ld\n", num); /* 213982 */
printf("%s\n", theRest); /* " and the rest" */
</code></pre>

blocks|key|1135189|text|根据strtol的atoi手册页，它已被弃用。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1135190|IMPLEMENTATION+NOTES
The+atoi()+and+atoi_l()+functions+have+been+deprecated+by+strtol()+and+strtol_l()+
and+should+not+be+used+in+new+code.|code-block|syntax|javascript|1135191|entityMap^0|2|6|9|4|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

According to the <code>atoi</code> man page, it has been deprecated by <code>strtol</code>.

<pre><code>IMPLEMENTATION NOTES
The atoi() and atoi_l() functions have been deprecated by strtol() and strtol_l() 
and should not be used in new code.
</code></pre>

blocks|key|920697|text|strtol的手册页提供了以下内容：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|920698|ERRORS
+++EINVAL+(not+in+C99)+The+given+base+contains+an+unsupported+value.
+++ERANGE+The+resulting+value+was+out+of+range.
+++The+implementation+may+also+set+errno+to+EINVAL+in+case+no+conversion+was+performed+(no+digits+seen,+and+0+returned).|code-block|syntax|javascript|920699|下面的代码检查范围错误。(修改了Eli的代码)|920700|#include+<stdio.h>
#include+<stdlib.h>
#include+<string.h>
#include+<errno.h>

int+main()
{
+++errno+=+0;
+++char*+end+=+0;
+++long+res+=+strtol("83459299999999999K997",+&end,+10);

+++if(errno+!=+0)
+++{
++++++printf("Conversion+error,+%25s\n",+strerror(errno));
+++}
+++else+if+(*end)
+++{
++++++printf("Converted+partially:+%25i,+non-convertible+part:+%25s\n",+res,+end);
+++}
+++else
+++{
++++++printf("Converted+successfully:+%25i\n",+res);
+++}

+++return+0;
}|920701|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

The man page of strtol gives the following:

<pre><code>ERRORS
 EINVAL (not in C99) The given base contains an unsupported value.
 ERANGE The resulting value was out of range.
 The implementation may also set errno to EINVAL in case no conversion was performed (no digits seen, and 0 returned).
</code></pre>

The following code checks for range errors. (Modified Eli's code a bit)

<pre><code>#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;errno.h&gt;

int main()
{
 errno = 0;
 char* end = 0;
 long res = strtol("83459299999999999K997", &amp;end, 10);

 if(errno != 0)
 {
 printf("Conversion error, %s\n", strerror(errno));
 }
 else if (*end)
 {
 printf("Converted partially: %i, non-convertible part: %s\n", res, end);
 }
 else
 {
 printf("Converted successfully: %i\n", res);
 }

 return 0;
}
</code></pre>

What is the difference between atol() &amp; strtol()?

According to their man pages, they seem to have the same effect as well as matching arguments:

<pre><code>long atol(const char *nptr);

long int strtol(const char *nptr, char **endptr, int base);
</code></pre>

In a generalized case, when I don't want to use the <code>base</code> argument (I just have decimal numbers), which function should I use?

atol() v/s. strtol()

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

atol()和strtol()有什么区别？根据他们的手册页，它们似乎具有相同的效果以及匹配的论点：long atol(const char *nptr);long int strtol(const char *nptr, char **endptr, int base);在一般情况下，当我不想使用base参数(我只有十...

问atol() v/s. strtol()
EN

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问atol() v/s. strtol()EN

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问atol() v/s. strtol()
EN