1. Recently, when using MDK to generate lib, Keil failed to call lib, resulting in a lot of undefined problems
2. When generating lib with keil for testing, you can’t add the header file to the project.
Delete all. H files, regenerate the Lib file, and call again. It is found that there will be no more problems such as error: l6218e: undefined symbol
When the project uses easyUI, the foreground reports an error, type error: A is undefined. I see that the error location is actually the source code of JQ… It’s impossible. I searched a lot of information on the Internet, but I didn’t solve the problem. After nearly a month’s thinking, I seem to have found the cause of this problem. It may not be right. It only represents personal profile. If there is a positive solution, please let me know. Thank you.
The error screenshot is as follows:
The reasons are as follows: I have such a piece of code in JS:
$('#cargo_info').datagrid().datagrid('getPager');Note that this code is not put in any function, nor is it wrapped with $(function () {}). Just this sentence is put directly in JS code. This is all the cases that report this error in my project. My preliminary analysis is because JS thinks that there is no method to call this sentence, so it reports an error.
Solution: wrap the isolated statements in JS with $(function () {}), or write them in a function,
<pre name="code" class="javascript">$(function(){
$('#cargo_info').datagrid().datagrid('getPager');
})Like this, you can’t make a mistake at the front desk
bmeta_info.cpp:4280: undefined reference to ‘crypt’
collect2: ld returned 1 exit status
Information found online shows:
Undefined reference to error: this type of error is in the process of connection, there may be two reasons: one is the user to define a function or global variable in a source code file that is not compile, link, or simply has not been defined, it requires the user to modify source program according to the practical situation, presents the definition of a global variable or function body; The second is that the undefined symbol is a standard library function, which is used in the source program, and the corresponding library name is not given during the connection process, or the directory name of the archive has a problem
Use the Man crypt command to find the following information:
GNU EXTENSION
The glibc2 version of this function has the following additional features. If salt is a character string starting with the three characters "$1$" followed by at most eight characters, and optionally terminated by "$", then instead of using the DES machine, the glibc crypt function uses an MD5-based algorithm, and outputs up to 34 bytes, namely "$1$<string>$", where "<string>" stands for the up to 8 characters following "$1$" in the salt, followed by 22 bytes chosen from the set [a–zA–Z0–9./]. The entire key is significant here (instead of only the first 8 bytes).
Programs using this function must be linked with -lcrypt.Program using this function must be linked with -lcrypt. The program must be linked with -lcrypt
Reference: [http://blog.sina.com.cn/s/blog_64c238860100wzoo.html]