libopenmpt  0.7.0-pre.10+r17981
cross-platform C++ and C library to decode tracked music files
libopenmpt Style Guide


Note: This applies to libopenmpt/ and openmpt123/ directories only. Use OpenMPT style otherwise.

The code generally tries to follow these conventions, but they are not strictly enforced and there are valid reasons to diverge from these conventions. Using common sense is recommended.

  • In general, the most important thing is to keep style consistent with directly surrounding code.
  • Use C++ std types when possible, prefer std::size_t and std::int32_t over long or int. Do not use C99 std types (e.g. no pure int32_t)
  • Qualify namespaces explicitly, do not use using. Members of namespace openmpt can be named without full namespace qualification.
  • Prefer the C++ version in namespace std if the same functionality is provided by the C standard library as well. Also, include the C++ version of C standard library headers (e.g. use <cstdio> instead of <stdio.h>.
  • Do not use ANY locale-dependant C functions. For locale-dependant C++ functionaly (especially iostream), always imbue the std::locale::classic() locale.
  • Prefer kernel_style_names over CamelCaseNames.
  • If a folder (or one of its parent folders) contains .clang-format, use clang-format v3.5 for indenting C++ and C files, otherwise:
    • { are placed at the end of the opening line.
    • Enclose even single statements in curly braces.
    • Avoid placing single statements on the same line as the if.
    • Opening parentheses are separated from keywords with a space.
    • Opening parentheses are not separated from function names.
    • Place spaces around operators and inside parentheses.
    • Align : and , when inheriting or initializing members in a constructor.
    • The pointer * is separated from both the type and the variable name.
    • Use tabs for identation, spaces for formatting. Tabs should only appear at the very beginning of a line. Do not assume any particular width of the TAB character. If width is important for formatting reasons, use spaces.
    • Use empty lines at will.
  • API documentation is done with doxygen. Use general C doxygen for the C API. Use QT-style doxygen for the C++ API.

libopenmpt indentation example

namespace openmpt {
// This is totally meaningless code and just illustrates indentation.
class foo
: public base
, public otherbase
std::int32_t x;
std::int16_t y;
: x(0)
, y(-1)
int bar() const;
}; // class foo
int foo::bar() const {
for ( int i = 0; i < 23; ++i ) {
switch ( x ) {
case 2:
something( y );
something( ( y - 1 ) * 2 );
if ( x == 12 ) {
return -1;
} else if ( x == 42 ) {
return 1;
return 42;
} // namespace openmpt
Definition: libopenmpt.hpp:130