X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fshared%2Fmacro.h;h=dfbc20142f753172ee8708f5e5aa94eca27fa66b;hb=2d5bdf5bc0e4714d42e5999a4e37553a6bf83575;hp=79bee0396c3a52c4bed07f28f1878915bad8b282;hpb=919ce0b7affc6fbd68598b709faf477f56c22ac1;p=elogind.git

diff --git a/src/shared/macro.h b/src/shared/macro.h
index 79bee0396..dfbc20142 100644
--- a/src/shared/macro.h
+++ b/src/shared/macro.h
@@ -117,6 +117,13 @@ static inline size_t ALIGN_TO(size_t l, size_t ali) {
                         _a < _b ? _a : _b;      \
                 })
 
+#define LESS_BY(A,B)                            \
+        __extension__ ({                        \
+                        typeof(A) _A = (A);     \
+                        typeof(B) _B = (B);     \
+                        _A > _B ? _A - _B : 0;  \
+                })
+
 #ifndef CLAMP
 #define CLAMP(x, low, high)                                             \
         __extension__ ({                                                \