X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fstpncpy.m4;h=aebfe739b9b8df5ed7195c5e4fce52cba6e651f8;hb=2544ecc3ffdc44a0209c951cac5267d134352780;hp=768cced0270728269eb04510cdd5eca973a1eb8c;hpb=1080617a7d04cdf1a1d3b1e390859af371d485d7;p=gnulib.git

diff --git a/m4/stpncpy.m4 b/m4/stpncpy.m4
index 768cced02..aebfe739b 100644
--- a/m4/stpncpy.m4
+++ b/m4/stpncpy.m4
@@ -11,6 +11,16 @@ AC_DEFUN([gl_FUNC_STPNCPY],
   dnl Persuade glibc <string.h> to declare stpncpy().
   AC_REQUIRE([AC_GNU_SOURCE])
 
+  dnl Both glibc and AIX (4.3.3, 5.1) have an stpncpy() function
+  dnl declared in <string.h>. Its side effects are the same as those
+  dnl of strncpy():
+  dnl      stpncpy (dest, src, n)
+  dnl overwrites dest[0..n-1], min(strlen(src),n) bytes coming from src,
+  dnl and the remaining bytes being NULs.  However, the return value is
+  dnl   in glibc:   dest + min(strlen(src),n)
+  dnl   in AIX:     dest + max(0,n-1)
+  dnl Only the glibc return value is useful in practice.
+
   AC_CACHE_CHECK([for working stpncpy], gl_cv_func_stpncpy, [
     AC_TRY_RUN([
 #include <stdlib.h>
@@ -42,8 +52,6 @@ int main () {
       [Define if you have the stpncpy() function and it works.])
   else
     AC_LIBOBJ([stpncpy])
-    AC_DEFINE(stpncpy, rpl_stpncpy,
-      [Define to rpl_stpncpy if the replacement function should be used.])
     gl_PREREQ_STPNCPY
   fi
 ])