Development/Code Conventions

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Code Conventions

Most of the LibreOffice code is written with C++, but there are also many source code files that are in Java, Python and BASIC. LibreOffice uses specific coding conventions, in naming, data type and many other things. Following those conventions helps keeping the code clean and readable.

LibreOffice Data Types

Note: Data types are discussed in more details in LibreOffice Developer's Guide. To learn more, please refer to first chapter of the LibreOffice Developer's Guide.

The data types that are listed in the following table are used for members of structs, as method return types or method parameters. Also, mappings to Java, C++, and LibreOffice Basic types are provided.

UNO	Type description	Java	C++	Basic
void	empty type, used only as method return type and in any	void	void	-
boolean	Boolean type; true and false	boolean	bool (sal_Bool is deprecated)	Boolean
byte	signed 8-bit integer type	byte	sal_Int8	Integer
short	signed 16-bit integer type	short	sal_Int16	Integer
unsigned short	unsigned 16-bit integer type (deprecated)	-	sal_uInt16	-
long	signed 32-bit integer type	int	sal_Int32	Long
unsigned long	unsigned 32-bit integer type (deprecated)	-	sal_uInt32	-
hyper	signed 64-bit integer type	long	sal_Int64	-
unsigned hyper	unsigned 64-bit integer type (deprecated)	-	sal_uInt64	-
float	IEC 60559 single precision floating point type	float	float (if appropriate)	Single
double	IEC 60559 double precision floating point type	double	double (if appropriate)	Double
char	16-bit Unicode character type (more precisely: UTF-16 code units)-	char	sal_Unicode	-
string	Unicode string type (more precisely: strings of Unicode scalar values)	java.lang.­String	rtl::OUString	String

C++ Code Conventions

LibreOffice uses C++ 20 as the standard for the code base. Therefore, you can use the latest features that are available in C++20.

On the other hand, there are things that are specific to LibreOffice source code. In order to make it possible to have interoperability across different operating systems and different programming languages for the LibreOffice API, LibreOffice has its own set of data types, as discussed above.

Code Formatting

For the newer files, you should use the tool clang-format, to re-format your code. Otherwise, CI will not accept your submitted code.

Naming Conventions

In LibreOffice C++ code, there are specific rules for naming variables according to their data types. That is helpful to learn about the data type of a variable by just looking into its prefix.

Data Type	Template	Example
(Smart) pointer/reference to a UNO interface	xName	xContext
(Smart) pointer to anything else	pName	pControl
Reference to anything else	rName	rTopic
Integer value	nName	nWhich
Floating-point number	fName	fWidth
Boolean	bName, or isName, or canName	isEndOfSentence
String	optionally sName (for char * -> pName; for OUString -> aName	sDateFormat
Another object	aName	aActual