https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77762
Bug ID: 77762
Summary: Incorrect destination buffer length in -Wformat-length
warning
Product: gcc
Version: 7.0
Status: UNCONFIRMED
Keywords: diagnostic
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: fw at gcc dot gnu.org
CC: msebor at gcc dot gnu.org
Target Milestone: ---
Created attachment 39703
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39703&action=edit
dbg_log.c
The attached test case, extracted from nscd/dbg_log.c in glibc, prints (when
compiled with -O2 -Wall):
dbg_log.c: In function ‘dbg_log’:
dbg_log.c:11:10: warning: specified size 512 exceeds the size 1 of the
destination object [-Wformat-length=]
return __builtin___vsnprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
__bos (__s), __fmt, __ap);
~~~~~~~~~~~~~~~~~~~~~~~~~
This appears to be different from bug 77743 because GCC should not have buffer
length information in this case.
