From b35e9606846636b7505efb078b16f34deb42f961 Mon Sep 17 00:00:00 2001 From: bnewbold Date: Sun, 26 Jun 2011 14:53:31 -0400 Subject: old c notes --- software/c.page | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 software/c.page (limited to 'software') diff --git a/software/c.page b/software/c.page new file mode 100644 index 0000000..910a5de --- /dev/null +++ b/software/c.page @@ -0,0 +1,44 @@ + +C Programming Language +======================= + +K&R Notes (unstructured) +----------------------------- + +With pointer arithmatic, the type of ``foo *p`` is taken into account +automagically. Eg, ``p+3`` -> ``0xFEFE0000 + 3 * (sizeof foo)``. + +Examples of tricky pointer sytax:: + + int *ip; + (++*p) + (*p++) + ++(*p) + *(++p) + +In the context of references like function declarations, only the size of the +first dimension of a multi-dimensional array is free; the others must be +specified explicitly:: + + void copy_2d_array(int a[][10], int b[][10]); // Ok + void copy_2d_array(int a[][], int b[][]); // Invalid + void copy_2d_array(int a[10][], int b[10][]); // Invalid + +Negative indexing of arrays is "allowed" (reads ahead of the array in memory); +need to check for that case explicitly. + +``_FORTIFY_SOURCE`` does what it says. + +In C99 can ``int* p`` replace ``int *p``? Seems like yes. + +The "update statement" of a for loop gets executed at the /end/ of every loop, +which means an iteration variable gets updated once more than might be +expected:: + + int i; + for(i = 0; i < 10; i++) { + } + printf("%d\n", i); // prints 10, not 9 + +Any 'inline' should probably be 'static' (local linkage). + -- cgit v1.2.3