1 used in the macro definition:
#define CV_ARE_SIZES_EQ (MAT1, mat2) \
((mat1)->rows = = (MAT2)->rows && (mat1)->cols = = (MAT2)-> Cols
2 used in printf, sometimes the statement in printf is too long, need to be split, then use the
PHP extension text processing -- PCRE regular expression syntax 3 -- escape sequence (backslash) backlash has multiple usage. First, if it is followed by a non-alphanumeric character, it indicates that the special meaning represented by this
Instance
Add a backslash before each double quotation mark ("):
Definition and usage
The Addslashes () function returns a string that adds a backslash before a predefined character.
The predefined characters are:
Single quotation mark (')
Double
instance
Add a backslash before the character "W":
Definition and usage
The Addcslashes () function returns a string that adds a backslash before the specified character.
Note: the Addcslashes () function is case-sensitive.
Note: Be careful when
Today, I checked some of the content in the header file provided by VC. Many statements are followed by backslashes. In my impression, only // indicates the annotation function, however, the backslash is only an escape character. But I have never
The phpstripcslashes () function is used to delete the backslash added by the addcslashes () function. This function can be used to clear data retrieved from a database or an HTML form, this article introduces the usage and basic instances of
Instance
Remove the backslash in front of "world!":
Definition and usage
The Stripcslashes () function deletes a backslash added by the addcslashes () function.
Tip: This function can be used to clean up data retrieved from a database or from an
When there is too much code in your code, it is especially inconvenient to read the code, and you need to use a newline character "\". Be aware of two points when using line breaks:
The 1.c compiler is based on ";" To determine if it is a statement,
There are many places in the C language where macro definitions are used, such as in header files to prevent header files from being repeatedly included:
#ifndef ctest_header_h
#define CTEST_HEADER_H
/header file content
#endif
Many macro
I used to think that the definition of macro is very simple, there is no long macro function, the most commonly used is the definition of Max (), when writing a macro function today, relative to Max (), A little bit longer, and then stepped on a
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