X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=functions%2Fstring%2Fstrncpy.c;h=efb6480468391a0bf35fae0e8001bee7d0d5c1d9;hb=cd6cfe0f578c4f744ddc9a342243aff6b42f8027;hp=e1f34a7f8558b83734b0ce8cb967c809120de74e;hpb=0c76deec506f54fff7326da6b1dcaef5958777ec;p=pdclib.old

diff --git a/functions/string/strncpy.c b/functions/string/strncpy.c
index e1f34a7..efb6480 100644
--- a/functions/string/strncpy.c
+++ b/functions/string/strncpy.c
@@ -1,7 +1,5 @@
 /* $Id$ */
 
-/* Release $Name$ */
-
 /* strncpy( char *, const char *, size_t )
 
    This file is part of the Public Domain C Library (PDCLib).
@@ -18,11 +16,13 @@ char * strncpy( char * _PDCLIB_restrict s1, const char * _PDCLIB_restrict s2, si
     while ( ( n > 0 ) && ( *s1++ = *s2++ ) )
     {
         /* Cannot do "n--" in the conditional as size_t is unsigned and we have
-        to check it again for >0 in the next loop.
+           to check it again for >0 in the next loop below, so we must not risk
+           underflow.
         */
         --n;
     }
-    while ( --n )
+    /* Checking against 1 as we missed the last --n in the loop above. */
+    while ( n-- > 1 )
     {
         *s1++ = '\0';
     }
@@ -34,10 +34,9 @@ char * strncpy( char * _PDCLIB_restrict s1, const char * _PDCLIB_restrict s2, si
 #ifdef TEST
 #include <_PDCLIB_test.h>
 
-int main()
+int main( void )
 {
     char s[] = "xxxxxxx";
-    BEGIN_TESTS;
     TESTCASE( strncpy( s, "", 1 ) == s );
     TESTCASE( s[0] == '\0' );
     TESTCASE( s[1] == 'x' );
@@ -48,6 +47,10 @@ int main()
     TESTCASE( s[6] == 'x' );
     TESTCASE( strncpy( s, abcde, 7 ) == s );
     TESTCASE( s[6] == '\0' );
+    TESTCASE( strncpy( s, "xxxx", 3 ) == s );
+    TESTCASE( s[0] == 'x' );
+    TESTCASE( s[2] == 'x' );
+    TESTCASE( s[3] == 'd' );
     return TEST_RESULTS;
 }
 #endif