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| author | Richard Levitte <levitte@openssl.org> | 2024-04-17 13:56:26 +0200 |
|---|---|---|
| committer | Tomas Mraz <tomas@openssl.org> | 2024-05-22 09:59:32 +0200 |
| commit | 4e8c4b77ef7480b80de1971d8862300c366015e9 (patch) | |
| tree | dc9109da1c88f3dbf32f6cceb48ac1da57fd31fc /NOTES-ANSI.md | |
| parent | 8cf9ac9c2034eb383b72bb7a849b5db96ff593f6 (diff) | |
Add installation documentation and notes on ANSI C and POSIX
Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/24173)
Diffstat (limited to 'NOTES-ANSI.md')
| -rw-r--r-- | NOTES-ANSI.md | 33 |
1 files changed, 33 insertions, 0 deletions
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. |