101 lines
3.0 KiB
Markdown
101 lines
3.0 KiB
Markdown
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# Suppressions
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If you want to filter out certain errors you can suppress these.
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Please note that if you see a false positive then we (the Cppcheck team) want that you report it so we can fix it.
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## Plain text suppressions
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You can suppress certain types of errors. The format for such a suppression is one of:
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[error id]:[filename]:[line]
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[error id]:[filename2]
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[error id]
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The `error id` is the id that you want to suppress. The easiest way to get it is to use the --template=gcc command line flag. The id is shown in brackets.
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The filename may include the wildcard characters \* or ?, which match any sequence of characters or any single character respectively. It is recommended that you use "/" as path separator on all operating systems.
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## Command line suppression
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The `--suppress=` command line option is used to specify suppressions on the command line. Example:
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cppcheck --suppress=memleak:src/file1.cpp src/
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## Suppressions in a file
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You can create a suppressions file. Example:
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// suppress memleak and exceptNew errors in the file src/file1.cpp
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memleak:src/file1.cpp
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exceptNew:src/file1.cpp
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// suppress all uninitvar errors in all files
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uninitvar
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Note that you may add empty lines and comments in the suppressions file.
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You can use the suppressions file like this:
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cppcheck --suppressions-list=suppressions.txt src/
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## XML suppressions
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You can specify suppressions in a XML file. Example file:
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<?xml version="1.0"?>
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<suppressions>
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<suppress>
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<id>uninitvar</id>
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<fileName>src/file1.c</fileName>
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<lineNumber>10</lineNumber>
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<symbolName>var</symbolName>
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</suppress>
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</suppressions>
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The XML format is extensible and may be extended with further attributes in the future.
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You can use the suppressions file like this:
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cppcheck --suppress-xml=suppressions.xml src/
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## Inline suppressions
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Suppressions can also be added directly in the code by adding comments that contain special keywords. Before adding such comments, consider that the code readability is sacrificed a little.
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This code will normally generate an error message:
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void f() {
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char arr[5];
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arr[10] = 0;
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}
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The output is:
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cppcheck test.c
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[test.c:3]: (error) Array 'arr[5]' index 10 out of bounds
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To suppress the error message, a comment can be added:
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void f() {
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char arr[5];
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// cppcheck-suppress arrayIndexOutOfBounds
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arr[10] = 0;
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}
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Now the `--inline-suppr` flag can be used to suppress the warning. No error is reported when invoking cppcheck this way:
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cppcheck --inline-suppr test.c
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You can specify that the inline suppression only applies to a specific symbol:
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// cppcheck-suppress arrayIndexOutOfBounds symbolName=arr
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You can write comments for the suppress, however is recommended to use ; or // to specify where they start:
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// cppcheck-suppress arrayIndexOutOfBounds ; some comment
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// cppcheck-suppress arrayIndexOutOfBounds // some comment
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