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diff --git a/NOTES-ANSI.md b/NOTES-ANSI.md new file mode 100644 index 0000000000..feeb543485 --- /dev/null +++ b/NOTES-ANSI.md @@ -0,0 +1,33 @@ +Notes on ANSI C +=============== + +When building for pure ANSI C (C89/C90), you must configure with at least +the following configuration settings: + +- `no-asm` + + There are cases of `asm()` calls in our C source, which isn't supported + in pure ANSI C. + +- `no-secure-memory` + + The secure memory calls aren't supported with ANSI C. + +- `-D_XOPEN_SOURCE=1` + + This macro enables the use of the following types, functions and global + variables: + + - `timezone` + +- `-D_POSIX_C_SOURCE=200809L` + + This macro enables the use of the following types, functions and global + variables: + + - `ssize_t` + - `strdup()` + +It's arguable that with gcc and clang, all of these issues are removed when +defining the macro `_DEFAULT_SOURCE`. However, that effectively sets the C +language level to C99, which isn't ANSI C. |