diff options
Diffstat (limited to 'src/include/c.h')
| -rw-r--r-- | src/include/c.h | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/src/include/c.h b/src/include/c.h index 65ff45aa92..250a8c6db1 100644 --- a/src/include/c.h +++ b/src/include/c.h @@ -8,7 +8,7 @@ * Portions Copyright (c) 1996-2000, PostgreSQL, Inc * Portions Copyright (c) 1994, Regents of the University of California * - * $Id: c.h,v 1.75 2000/07/06 21:33:44 petere Exp $ + * $Id: c.h,v 1.76 2000/07/07 21:12:47 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -781,11 +781,19 @@ extern int assertTest(int val); /* * StrNCpy - * Like standard library function strncpy(), except that result string - * is guaranteed to be null-terminated --- that is, at most N-1 bytes - * of the source string will be kept. - * Also, the macro returns no result (too hard to do that without - * evaluating the arguments multiple times, which seems worse). + * Like standard library function strncpy(), except that result string + * is guaranteed to be null-terminated --- that is, at most N-1 bytes + * of the source string will be kept. + * Also, the macro returns no result (too hard to do that without + * evaluating the arguments multiple times, which seems worse). + * + * BTW: when you need to copy a non-null-terminated string (like a text + * datum) and add a null, do not do it with StrNCpy(..., len+1). That + * might seem to work, but it fetches one byte more than there is in the + * text object. One fine day you'll have a SIGSEGV because there isn't + * another byte before the end of memory. Don't laugh, we've had real + * live bug reports from real live users over exactly this mistake. + * Do it honestly with "memcpy(dst,src,len); dst[len] = '\0';", instead. */ #define StrNCpy(dst,src,len) \ do \ |