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author | bnewbold <bnewbold@robocracy.org> | 2011-06-26 14:53:31 -0400 |
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committer | bnewbold <bnewbold@robocracy.org> | 2011-06-26 14:53:31 -0400 |
commit | b35e9606846636b7505efb078b16f34deb42f961 (patch) | |
tree | c6577a33c29e4fd4e02b738ee1f2b09a1a5355af /software | |
parent | 85a603e6421aa9241632f1405d4f31ef06fcaff6 (diff) | |
download | knowledge-b35e9606846636b7505efb078b16f34deb42f961.tar.gz knowledge-b35e9606846636b7505efb078b16f34deb42f961.zip |
old c notes
Diffstat (limited to 'software')
-rw-r--r-- | software/c.page | 44 |
1 files changed, 44 insertions, 0 deletions
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). + |