https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92141
Bug ID: 92141
Summary: Bogus -Wstringop-truncation warning for strncpy in a
loop
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: krebbel at gcc dot gnu.org
Target Milestone: ---
Compiling the following testcase with: gcc -O2 -Wall t.c
char *strncpy(char *, const char *, long unsigned);
struct {
char b[8];
} c[6];
char b[8];
void e() {
for (int f = 0;; f++)
strncpy(b, c[f].b, 8);
}
gives me:
t.c: In function 'e':
t.c:8:5: warning: 'strncpy' output may be truncated copying 8 bytes from a
string of length 47 [-Wstringop-truncation]
8 | strncpy(b, c[f].b, 8);
| ^~~~~~~~~~~~~~~~~~~~~
