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f94002ec C |
1 | This is a partial list of how `gcc -traditional' disagrees with |
2 | traditional C compilers (perhaps only some of them). Most of these | |
3 | differences are not bugs. | |
4 | ||
5 | --------------------------------------------------------------------------- | |
6 | K&R-1 (2.4.3) says: | |
7 | ||
8 | "If the character following a backslash is not one of those | |
9 | specified {in the table above}, the backslash is ignored." | |
10 | ||
11 | Up until recently, `gcc -traditional' complained about \x \a and \v | |
12 | appearing in a character or string literal. I believe however that | |
13 | this non-feature has been eliminated (recently). | |
14 | ||
15 | --------------------------------------------------------------------------- | |
16 | When in -traditional mode, gcc allows the following erroneous pair of | |
17 | declarations to appear together in a given scope: | |
18 | ||
19 | typedef int foo; | |
20 | typedef foo foo; | |
21 | ||
22 | --------------------------------------------------------------------------- | |
23 | K&R-1 (8.5) says: | |
24 | ||
25 | "No field may be wider than a word." | |
26 | ||
27 | Gcc however allows: | |
28 | ||
29 | struct S { int i:33; }; | |
30 | ||
31 | --------------------------------------------------------------------------- | |
32 | In K&R-1 there is no restriction against comments crossing include file | |
33 | boundaries. Gcc however doesn't allow this, even when in -traditional mode. | |
34 | ||
35 | --------------------------------------------------------------------------- | |
36 | Regarding the length of identifiers, K&R-1 (2.2) says: | |
37 | ||
38 | "No more than the first eight characters are significant, | |
39 | although more may be used." | |
40 | ||
41 | Gcc treats all characters of identifiers as significant, even when in | |
42 | -traditional mode. | |
43 | ||
44 | --------------------------------------------------------------------------- | |
45 | K&R-1 (2.2) says: | |
46 | ||
47 | "An identifier is a sequence of letters and digits; the first | |
48 | character must be a letter. The underscore _ counts as a letter." | |
49 | ||
50 | Gcc also allows dollar signs in identifiers. (This may also be an issue | |
51 | for the -pedantic option.) | |
52 | ||
53 | --------------------------------------------------------------------------- | |
54 | ||
55 |