Re: prohibit_strcmp

[Jim Meyering]

Bruno Haible wrote:
>> That gnulib has two definitions is unfortunate, but I will not
>> volunteer to change the STREQ that I've been using ;-)
>> I don't see much value in streq.h, either, and hence, don't use it.
>
> The value of streq.h is an optimized definition which is used in a few
> places. I agree that your STREQ is more generally useful, especially to
> avoid thinkos, therefore I wouldn't want to rename yours.
>
> Akim suggests to rename STREQ in lib/streq.h; what name would you suggest?

STREQ_ retains the name and look while adding only one to the length.
STREQ_opt is more descriptive, but longer

>> I use STRNCMP_LIT defined in coreutils/src/system.h:
>>
>>     /* Just like strncmp, but the second argument must be a literal string
>>        and you don't specify the length.  */
>>     #define STRNCMP_LIT(s, literal) \
>>       strncmp (s, "" literal "", sizeof (literal) - 1)
>
> This comment is not clear enough. If someone writes
>   STRNCMP_LIT (s, "foobar")
> will it return true for s = "foobarbaz"? Will it return true for s = "foo"?
>
> How about reformulating the comment?
>
>   /* STRNCMP_LIT(S, PREFIX) returns true if the string S starts with the
>      prefix string PREFIX.  PREFIX must be a literal string.  */
>
> And given this specification, STRNCMP_LIT is an odd name. How about
> STR_HAS_PREFIX or STR_STARTS_WITH?

As Akim suggested, I think you'd want a different macro for that.
This one really does intend to return ternary <, =, > 0, like strncmp.
But I can improve the comment:

>From fbca75fddb6918c0667783a7805847fc3bf78578 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Fri, 24 Feb 2012 10:02:18 +0100
Subject: [PATCH] doc: clarify a comment in system.h

* src/system.h (STRNCMP_LIT): Clarify comment.
Suggested by Bruno Haible.
---
 src/system.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/system.h b/src/system.h
index c4f262d..f312f88 100644
--- a/src/system.h
+++ b/src/system.h
@@ -186,7 +186,7 @@ select_plural (uintmax_t n)
 #define STRPREFIX(a, b) (strncmp(a, b, strlen (b)) == 0)

 /* Just like strncmp, but the second argument must be a literal string
-   and you don't specify the length.  */
+   and you don't specify the length;  that comes from the literal.  */
 #define STRNCMP_LIT(s, literal) \
   strncmp (s, "" literal "", sizeof (literal) - 1)

--
1.7.9.2.235.g1d0cd