Re: [PATCH bpf-next v1 7/8] selftests/bpf: Fix using stdout, stderr as struct field names

On Thu, Jul 25, 2024 at 3:39 AM Tony Ambardar [off-list ref] wrote:

From: Tony Ambardar <redacted>

Typically stdin, stdout, stderr are treated as reserved identifiers under
ISO/ANSI C, and a libc implementation is free to define these as macros.

Ok, wow that. Do you have a pointer to where in the standard it is
said that stdin/stdout/stderr is some sort of reserved identifier that
can't be used as a field name?


I really don't like these underscored field names. If we have to
rename, I'd prefer something like env.saved_stdout instead of
env._stdout. But I'd prefer even more if musl wasn't doing this macro
definition, of course...

This is the case in musl libc and results in compile errors when these
names are reused as struct fields, as with 'struct test_env' and related
usage in test_progs.[ch] and reg_bounds.c.

Rename the fields to _stdout and _stderr to avoid many errors seen building
against musl, e.g.:

  In file included from test_progs.h:6,
                   from test_progs.c:5:
  test_progs.c: In function 'print_test_result':
  test_progs.c:237:21: error: expected identifier before '(' token
    237 |         fprintf(env.stdout, "#%-*d %s:", TEST_NUM_WIDTH, test->test_num, test->test_name);
        |                     ^~~~~~
  test_progs.c:237:9: error: too few arguments to function 'fprintf'
    237 |         fprintf(env.stdout, "#%-*d %s:", TEST_NUM_WIDTH, test->test_num, test->test_name);
        |         ^~~~~~~

Signed-off-by: Tony Ambardar <redacted>
---
 .../selftests/bpf/prog_tests/reg_bounds.c     |  2 +-
 tools/testing/selftests/bpf/test_progs.c      | 66 +++++++++----------
 tools/testing/selftests/bpf/test_progs.h      |  8 +--
 3 files changed, 38 insertions(+), 38 deletions(-)

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