Re: [PATCH] autoconf: Add link tests to each AC_CHECK_FUNC() test

[Junio C Hamano <gitster@pobox.com>]

"David M. Syzdek" <david.syzdek@acsalaska.net> writes:

> Update configure.ac to test libraries for getaddrinfo, strcasestr, memmem,
> strlcpy, strtoumax, setenv, unsetenv, and mkdtemp.  The default compilers
> on FreeBSD 4.9-SECURITY and FreeBSD 6.2-RELEASE-p4 do not generate warnings
> for missing prototypes unless `-Wall' is used. This behavior renders the
> results of AC_CHECK_FUNC() void on these platforms. The test AC_SEARCH_LIBS()
> verifies a function is valid by linking to symbol within the system libraries.

> diff --git a/configure.ac b/configure.ac
> index 7c2856e..d3b8bc3 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -293,9 +293,11 @@ AC_SUBST(NO_SOCKADDR_STORAGE)
>  #
>  # Define NO_IPV6 if you lack IPv6 support and getaddrinfo().
>  AC_CHECK_TYPE([struct addrinfo],[
> - AC_CHECK_FUNC([getaddrinfo],
> -  [NO_IPV6=],
> -  [NO_IPV6=YesPlease])
> + AC_CHECK_FUNC([getaddrinfo],[
> +  AC_SEARCH_LIBS([getaddrinfo],,
> +    [NO_IPV6=],
> +    [NO_IPV6=YesPlease])
> + ],[NO_IPV6=YesPlease])

It's been a looong time since I did any sizeable autoconf/m4 hacking, but
the repetitititiveness of this patch loudly calls for a convenience macro
of a higher order, perhaps something like:

        AC_DEFUN([GIT_CHECK_FUNC],[
         AC_CHECK_FUNC([$1],[
          AC_SEARCH_LIBS([$1},,
          [$2],[$3])],
          [$3])])

Then we can use it like:

	GIT_CHECK_FUNC([getaddrinfo],[NO_IPV6=],[NO_IPV6=YesPlease])

Hmm?

-- >8 --
[PATCH] autoconf: use AC_CHECK_FUNC() with AC_SEARCH_LIBS() test

Update configure.ac to test libraries for getaddrinfo, strcasestr, memmem,
strlcpy, strtoumax, setenv, unsetenv, and mkdtemp.  The default compilers
on FreeBSD 4.9-SECURITY and FreeBSD 6.2-RELEASE-p4 do not generate warnings
for missing prototypes unless `-Wall' is used. This behavior renders the
results of AC_CHECK_FUNC() void on these platforms. The test AC_SEARCH_LIBS()
verifies a function is valid by linking to symbol within the system libraries.

---
 configure.ac |   28 +++++++++++++++++++---------
 1 files changed, 19 insertions(+), 9 deletions(-)

diff --git c/configure.ac w/configure.ac
index 27bab00..ef544e8 100644
--- c/configure.ac
+++ w/configure.ac
@@ -65,7 +65,17 @@ else \
 fi \
 ])# GIT_PARSE_WITH
 
-
+dnl
+dnl GIT_CHECK_FUNC(FUNCTION, IFTRUE, IFFALSE)
+dnl -----------------------------------------
+dnl Similar to AC_CHECK_FUNC, but on systems that do not generate
+dnl warnings for missing prototypes (e.g. FreeBSD when compiling without
+dnl -Wall), it does not work.  By looking for function definition in
+dnl libraries, this problem can be worked around.
+AC_DEFUN([GIT_CHECK_FUNC],[AC_CHECK_FUNC([$1],[
+  AC_SEARCH_LIBS([$1],,
+  [$2],[$3])
+],[$3])])
 ## Site configuration related to programs (before tests)
 ## --with-PACKAGE[=ARG] and --without-PACKAGE
 #
@@ -325,7 +335,7 @@ AC_SUBST(NO_SOCKADDR_STORAGE)
 #
 # Define NO_IPV6 if you lack IPv6 support and getaddrinfo().
 AC_CHECK_TYPE([struct addrinfo],[
- AC_CHECK_FUNC([getaddrinfo],
+ GIT_CHECK_FUNC([getaddrinfo],
   [NO_IPV6=],
   [NO_IPV6=YesPlease])
 ],[NO_IPV6=YesPlease],[
@@ -419,43 +429,43 @@ AC_SUBST(SNPRINTF_RETURNS_BOGUS)
 AC_MSG_NOTICE([CHECKS for library functions])
 #
 # Define NO_STRCASESTR if you don't have strcasestr.
-AC_CHECK_FUNC(strcasestr,
+GIT_CHECK_FUNC(strcasestr,
 [NO_STRCASESTR=],
 [NO_STRCASESTR=YesPlease])
 AC_SUBST(NO_STRCASESTR)
 #
 # Define NO_MEMMEM if you don't have memmem.
-AC_CHECK_FUNC(memmem,
+GIT_CHECK_FUNC(memmem,
 [NO_MEMMEM=],
 [NO_MEMMEM=YesPlease])
 AC_SUBST(NO_MEMMEM)
 #
 # Define NO_STRLCPY if you don't have strlcpy.
-AC_CHECK_FUNC(strlcpy,
+GIT_CHECK_FUNC(strlcpy,
 [NO_STRLCPY=],
 [NO_STRLCPY=YesPlease])
 AC_SUBST(NO_STRLCPY)
 #
 # Define NO_STRTOUMAX if you don't have strtoumax in the C library.
-AC_CHECK_FUNC(strtoumax,
+GIT_CHECK_FUNC(strtoumax,
 [NO_STRTOUMAX=],
 [NO_STRTOUMAX=YesPlease])
 AC_SUBST(NO_STRTOUMAX)
 #
 # Define NO_SETENV if you don't have setenv in the C library.
-AC_CHECK_FUNC(setenv,
+GIT_CHECK_FUNC(setenv,
 [NO_SETENV=],
 [NO_SETENV=YesPlease])
 AC_SUBST(NO_SETENV)
 #
 # Define NO_UNSETENV if you don't have unsetenv in the C library.
-AC_CHECK_FUNC(unsetenv,
+GIT_CHECK_FUNC(unsetenv,
 [NO_UNSETENV=],
 [NO_UNSETENV=YesPlease])
 AC_SUBST(NO_UNSETENV)
 #
 # Define NO_MKDTEMP if you don't have mkdtemp in the C library.
-AC_CHECK_FUNC(mkdtemp,
+GIT_CHECK_FUNC(mkdtemp,
 [NO_MKDTEMP=],
 [NO_MKDTEMP=YesPlease])
 AC_SUBST(NO_MKDTEMP)