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| -rw-r--r-- | Documentation/coding-style.rst | 14 | ||||
| -rwxr-xr-x | utils/checkstyle.py | 6 |
2 files changed, 14 insertions, 6 deletions
diff --git a/Documentation/coding-style.rst b/Documentation/coding-style.rst index 7c56a1b7..8af06d6a 100644 --- a/Documentation/coding-style.rst +++ b/Documentation/coding-style.rst @@ -195,9 +195,17 @@ them, defines C compatibility headers. The former have a name of the form <cxxx> while the later are named <xxx.h>. The C++ headers declare names in the std namespace, and may declare the same names in the global namespace. The C compatibility headers declare names in the global namespace, and may declare -the same names in the std namespace. Usage of the C compatibility headers is -strongly preferred. Code shall not rely on the optional declaration of names in -the global or std namespace. +the same names in the std namespace. Code shall not rely on the optional +declaration of names in the global or std namespace. + +Usage of the C compatibility headers is preferred, except for the math.h header. +Where math.h defines separate functions for different argument types (e.g. +abs(int), labs(long int), fabs(double) and fabsf(float)) and requires the +developer to pick the right function, cmath defines overloaded functions +(std::abs(int), std::abs(long int), std::abs(double) and std::abs(float) to let +the compiler select the right function. This avoids potential errors such as +calling abs(int) with a float argument, performing an unwanted implicit integer +conversion. For this reason, cmath is preferred over math.h. Documentation diff --git a/utils/checkstyle.py b/utils/checkstyle.py index b594a19a..d5dc26c0 100755 --- a/utils/checkstyle.py +++ b/utils/checkstyle.py @@ -244,9 +244,9 @@ class IncludeChecker(StyleChecker): patterns = ('*.cpp', '*.h') headers = ('assert', 'ctype', 'errno', 'fenv', 'float', 'inttypes', - 'limits', 'locale', 'math', 'setjmp', 'signal', 'stdarg', - 'stddef', 'stdint', 'stdio', 'stdlib', 'string', 'time', 'uchar', - 'wchar', 'wctype') + 'limits', 'locale', 'setjmp', 'signal', 'stdarg', 'stddef', + 'stdint', 'stdio', 'stdlib', 'string', 'time', 'uchar', 'wchar', + 'wctype') include_regex = re.compile('^#include <c([a-z]*)>') def __init__(self, content): |