Suppose we have a variable message with the value It's a beautiful day!. escaped_message = $(subst $(squote),'$(squote)',$(message)) shouldn't the result be It'$(squote)'s a beautiful day! ? If so, the return result will have two single quote, isn't wrong?
时间: 2024-02-18 07:59:28 浏览: 26
Yes, you are correct. The result of the command `escaped_message = $(subst $(squote),'$(squote)',$(message))` will indeed have two single quotes, which is not what we want.
A better way to escape the single quote in `$(message)` is to replace it with a backslash followed by a single quote (`\'`), like this:
```
escaped_message = $(subst ','\'',$(message))
```
This will replace all single quotes in `$(message)` with the escaped sequence `\'`, which represents a single quote. The resulting value of `escaped_message` will be `It\'s a beautiful day!`, which correctly escapes the single quote without adding any extra quotes.
相关问题
Suppose we have a variable message with the value It's a beautiful day!. If we want to use this variable in a makefile command, we need to escape the single quote character (') so that the command is properly interpreted. We can do this using the subst function like so: 复制 escaped_message = $(subst $(squote),'\$(squote)',$(message)) escaped_message would have the value It'\$(squote)s a beautiful day! Did you made a mistake by "It'\$(squote)s a beautiful day!"?
I apologize for the mistake. The correct value of `escaped_message` after the substitution would be `It\'s a beautiful day!`.
So, the command should be:
```
escaped_message = $(subst $(squote),'\$(squote)',$(message))
```
This will replace any instances of the `$(squote)` variable (which is set to a single quote character) in the `message` variable with `'\$(squote)'`, effectively escaping the single quotes.
In this example, `escaped_message` would have the value `It\'s a beautiful day!`. We can then use this variable in a makefile command without any issues.
escchar = $(subst $(squote),'\$(squote)',$1) give me an example based on this
Sure, here's an example:
Suppose we have a variable `message` with the value `It's a beautiful day!`. If we want to use this variable in a makefile command, we need to escape the single quote character (`'`) so that the command is properly interpreted. We can do this using the `subst` function like so:
```
escaped_message = $(subst $(squote),'\$(squote)',$(message))
```
This will replace any instances of the `$(squote)` variable (which is set to a single quote character) in the `message` variable with `'\$(squote)'`, effectively escaping the single quotes.
So, in this example, `escaped_message` would have the value `It'\$(squote)s a beautiful day!`. We can then use this variable in a makefile command without any issues.