1 // RUN: %clang_cc1 -fblocks -fsyntax-only -verify -Wformat-nonliteral -isystem %S/Inputs %s
2 // RUN: %clang_cc1 -fblocks -fsyntax-only -verify -Wformat-nonliteral -isystem %S/Inputs -fno-signed-char %s
3 // RUN: %clang_cc1 -fblocks -fsyntax-only -verify -Wformat-nonliteral -isystem %S/Inputs -triple=x86_64-unknown-fuchsia %s
4 // RUN: %clang_cc1 -fblocks -fsyntax-only -verify -Wformat-nonliteral -isystem %S/Inputs -triple=x86_64-linux-android %s
5
6 #include <stdarg.h>
7 #include <stddef.h>
8 #define __need_wint_t
9 #include <stddef.h> // For wint_t and wchar_t
10
11 typedef struct _FILE FILE;
12 int fprintf(FILE *, const char *restrict, ...);
13 int printf(const char *restrict, ...); // expected-note{{passing argument to parameter here}}
14 int snprintf(char *restrict, size_t, const char *restrict, ...);
15 int sprintf(char *restrict, const char *restrict, ...);
16 int vasprintf(char **, const char *, va_list);
17 int asprintf(char **, const char *, ...);
18 int vfprintf(FILE *, const char *restrict, va_list);
19 int vprintf(const char *restrict, va_list);
20 int vsnprintf(char *, size_t, const char *, va_list);
21 int vsprintf(char *restrict, const char *restrict, va_list); // expected-note{{passing argument to parameter here}}
22
23 int vscanf(const char *restrict format, va_list arg);
24
25 char * global_fmt;
26
check_string_literal(FILE * fp,const char * s,char * buf,...)27 void check_string_literal( FILE* fp, const char* s, char *buf, ... ) {
28
29 char * b;
30 va_list ap;
31 va_start(ap,buf);
32
33 printf(s); // expected-warning {{format string is not a string literal}}
34 // expected-note@-1{{treat the string as an argument to avoid this}}
35 vprintf(s,ap); // expected-warning {{format string is not a string literal}}
36 fprintf(fp,s); // expected-warning {{format string is not a string literal}}
37 // expected-note@-1{{treat the string as an argument to avoid this}}
38 vfprintf(fp,s,ap); // expected-warning {{format string is not a string literal}}
39 asprintf(&b,s); // expected-warning {{format string is not a string lit}}
40 // expected-note@-1{{treat the string as an argument to avoid this}}
41 vasprintf(&b,s,ap); // expected-warning {{format string is not a string literal}}
42 sprintf(buf,s); // expected-warning {{format string is not a string literal}}
43 // expected-note@-1{{treat the string as an argument to avoid this}}
44 snprintf(buf,2,s); // expected-warning {{format string is not a string lit}}
45 // expected-note@-1{{treat the string as an argument to avoid this}}
46 __builtin___sprintf_chk(buf,0,-1,s); // expected-warning {{format string is not a string literal}}
47 // expected-note@-1{{treat the string as an argument to avoid this}}
48 __builtin___snprintf_chk(buf,2,0,-1,s); // expected-warning {{format string is not a string lit}}
49 // expected-note@-1{{treat the string as an argument to avoid this}}
50 vsprintf(buf,s,ap); // expected-warning {{format string is not a string lit}}
51 vsnprintf(buf,2,s,ap); // expected-warning {{format string is not a string lit}}
52 vsnprintf(buf,2,global_fmt,ap); // expected-warning {{format string is not a string literal}}
53 __builtin___vsnprintf_chk(buf,2,0,-1,s,ap); // expected-warning {{format string is not a string lit}}
54 __builtin___vsnprintf_chk(buf,2,0,-1,global_fmt,ap); // expected-warning {{format string is not a string literal}}
55
56 vscanf(s, ap); // expected-warning {{format string is not a string literal}}
57
58 const char *const fmt = "%d"; // FIXME -- defined here
59 printf(fmt, 1, 2); // expected-warning{{data argument not used}}
60
61 printf("abc"
62 "%*d", 1, 1); // no-warning
63 printf("abc\
64 def"
65 "%*d", 1, 1); // no-warning
66
67 // Allow 'unsigned' (instead of 'int') to be used for both the field width
68 // and precision. This deviates from C99, but is reasonably safe and is also
69 // accepted by GCC.
70 printf("%*d", (unsigned) 1, 1); // no-warning
71 }
72
73 // When calling a non-variadic format function (vprintf, vscanf, NSLogv, ...),
74 // warn only if the format string argument is a parameter that is not itself
75 // declared as a format string with compatible format.
76 __attribute__((__format__ (__printf__, 2, 4)))
check_string_literal2(FILE * fp,const char * s,char * buf,...)77 void check_string_literal2( FILE* fp, const char* s, char *buf, ... ) {
78 char * b;
79 va_list ap;
80 va_start(ap,buf);
81
82 printf(s); // expected-warning {{format string is not a string literal}}
83 // expected-note@-1{{treat the string as an argument to avoid this}}
84 vprintf(s,ap); // no-warning
85 fprintf(fp,s); // expected-warning {{format string is not a string literal}}
86 // expected-note@-1{{treat the string as an argument to avoid this}}
87 vfprintf(fp,s,ap); // no-warning
88 asprintf(&b,s); // expected-warning {{format string is not a string lit}}
89 // expected-note@-1{{treat the string as an argument to avoid this}}
90 vasprintf(&b,s,ap); // no-warning
91 sprintf(buf,s); // expected-warning {{format string is not a string literal}}
92 // expected-note@-1{{treat the string as an argument to avoid this}}
93 snprintf(buf,2,s); // expected-warning {{format string is not a string lit}}
94 // expected-note@-1{{treat the string as an argument to avoid this}}
95 __builtin___vsnprintf_chk(buf,2,0,-1,s,ap); // no-warning
96
97 vscanf(s, ap); // expected-warning {{format string is not a string literal}}
98 }
99
check_conditional_literal(const char * s,int i)100 void check_conditional_literal(const char* s, int i) {
101 printf(i == 1 ? "yes" : "no"); // no-warning
102 printf(i == 0 ? (i == 1 ? "yes" : "no") : "dont know"); // no-warning
103 printf(i == 0 ? (i == 1 ? s : "no") : "dont know"); // expected-warning{{format string is not a string literal}}
104 // expected-note@-1{{treat the string as an argument to avoid this}}
105 printf("yes" ?: "no %d", 1); // expected-warning{{data argument not used by format string}}
106 printf(0 ? "yes %s" : "no %d", 1); // no-warning
107 printf(0 ? "yes %d" : "no %s", 1); // expected-warning{{format specifies type 'char *'}}
108
109 printf(0 ? "yes" : "no %d", 1); // no-warning
110 printf(0 ? "yes %d" : "no", 1); // expected-warning{{data argument not used by format string}}
111 printf(1 ? "yes" : "no %d", 1); // expected-warning{{data argument not used by format string}}
112 printf(1 ? "yes %d" : "no", 1); // no-warning
113 printf(i ? "yes" : "no %d", 1); // no-warning
114 printf(i ? "yes %s" : "no %d", 1); // expected-warning{{format specifies type 'char *'}}
115 printf(i ? "yes" : "no %d", 1, 2); // expected-warning{{data argument not used by format string}}
116
117 printf(i ? "%*s" : "-", i, s); // no-warning
118 printf(i ? "yes" : 0 ? "no %*d" : "dont know %d", 1, 2); // expected-warning{{data argument not used by format string}}
119 printf(i ? "%i\n" : "%i %s %s\n", i, s); // expected-warning{{more '%' conversions than data arguments}}
120 }
121
122 #if !defined(__ANDROID__) && !defined(__Fuchsia__)
123
check_writeback_specifier(void)124 void check_writeback_specifier(void)
125 {
126 int x;
127 char *b;
128 printf("%n", b); // expected-warning{{format specifies type 'int *' but the argument has type 'char *'}}
129 printf("%n", &x); // no-warning
130
131 printf("%hhn", (signed char*)0); // no-warning
132 printf("%hhn", (char*)0); // no-warning
133 printf("%hhn", (unsigned char*)0); // no-warning
134 printf("%hhn", (int*)0); // expected-warning{{format specifies type 'signed char *' but the argument has type 'int *'}}
135
136 printf("%hn", (short*)0); // no-warning
137 printf("%hn", (unsigned short*)0); // no-warning
138 printf("%hn", (int*)0); // expected-warning{{format specifies type 'short *' but the argument has type 'int *'}}
139
140 printf("%n", (int*)0); // no-warning
141 printf("%n", (unsigned int*)0); // no-warning
142 printf("%n", (char*)0); // expected-warning{{format specifies type 'int *' but the argument has type 'char *'}}
143
144 printf("%ln", (long*)0); // no-warning
145 printf("%ln", (unsigned long*)0); // no-warning
146 printf("%ln", (int*)0); // expected-warning{{format specifies type 'long *' but the argument has type 'int *'}}
147
148 printf("%lln", (long long*)0); // no-warning
149 printf("%lln", (unsigned long long*)0); // no-warning
150 printf("%lln", (int*)0); // expected-warning{{format specifies type 'long long *' but the argument has type 'int *'}}
151
152 printf("%qn", (long long*)0); // no-warning
153 printf("%qn", (unsigned long long*)0); // no-warning
154 printf("%qn", (int*)0); // expected-warning{{format specifies type 'long long *' but the argument has type 'int *'}}
155
156 printf("%Ln", 0); // expected-warning{{length modifier 'L' results in undefined behavior or no effect with 'n' conversion specifier}}
157 // expected-note@-1{{did you mean to use 'll'?}}
158 }
159
160 #else
161
check_writeback_specifier(void)162 void check_writeback_specifier(void)
163 {
164 int x;
165 printf("%n", &x); // expected-warning{{'%n' specifier not supported on this platform}}
166
167 printf("%hhn", (signed char*)0); // expected-warning{{'%n' specifier not supported on this platform}}
168 printf("%hhn", (char*)0); // expected-warning{{'%n' specifier not supported on this platform}}
169 printf("%hhn", (unsigned char*)0); // expected-warning{{'%n' specifier not supported on this platform}}
170 printf("%hhn", (int*)0); // expected-warning{{format specifies type 'signed char *' but the argument has type 'int *'}}
171 // expected-warning@-1 {{'%n' specifier not supported on this platform}}
172
173 printf("%hn", (short*)0); // expected-warning{{'%n' specifier not supported on this platform}}
174 printf("%hn", (unsigned short*)0); // expected-warning{{'%n' specifier not supported on this platform}}
175 printf("%hn", (int*)0); // expected-warning{{format specifies type 'short *' but the argument has type 'int *'}}
176 // expected-warning@-1 {{'%n' specifier not supported on this platform}}
177
178 printf("%n", (int*)0); // expected-warning{{'%n' specifier not supported on this platform}}
179 printf("%n", (unsigned int*)0); // expected-warning{{'%n' specifier not supported on this platform}}
180 printf("%n", (char*)0); // expected-warning{{format specifies type 'int *' but the argument has type 'char *'}}
181 // expected-warning@-1 {{'%n' specifier not supported on this platform}}
182
183 printf("%ln", (long*)0); // expected-warning{{'%n' specifier not supported on this platform}}
184 printf("%ln", (unsigned long*)0); // expected-warning{{'%n' specifier not supported on this platform}}
185 printf("%ln", (int*)0); // expected-warning{{format specifies type 'long *' but the argument has type 'int *'}}
186 // expected-warning@-1 {{'%n' specifier not supported on this platform}}
187
188 printf("%lln", (long long*)0); // expected-warning{{'%n' specifier not supported on this platform}}
189 printf("%lln", (unsigned long long*)0); // expected-warning{{'%n' specifier not supported on this platform}}
190 printf("%lln", (int*)0); // expected-warning{{format specifies type 'long long *' but the argument has type 'int *'}}
191 // expected-warning@-1 {{'%n' specifier not supported on this platform}}
192
193 printf("%qn", (long long*)0); // expected-warning{{'%n' specifier not supported on this platform}}
194 printf("%qn", (unsigned long long*)0); // expected-warning{{'%n' specifier not supported on this platform}}
195 }
196
197 #endif // !defined(__ANDROID__) && !defined(__Fuchsia__)
198
check_invalid_specifier(FILE * fp,char * buf)199 void check_invalid_specifier(FILE* fp, char *buf)
200 {
201 printf("%s%lv%d","unix",10,20); // expected-warning {{invalid conversion specifier 'v'}} expected-warning {{data argument not used by format string}}
202 fprintf(fp,"%%%l"); // expected-warning {{incomplete format specifier}}
203 sprintf(buf,"%%%%%ld%d%d", 1, 2, 3); // expected-warning{{format specifies type 'long' but the argument has type 'int'}}
204 snprintf(buf, 2, "%%%%%ld%;%d", 1, 2, 3); // expected-warning{{format specifies type 'long' but the argument has type 'int'}} expected-warning {{invalid conversion specifier ';'}} expected-warning {{data argument not used by format string}} \
205 // expected-warning{{'snprintf' will always be truncated; specified size is 2, but format string expands to at least 7}}
206 }
207
check_null_char_string(char * b)208 void check_null_char_string(char* b)
209 {
210 printf("\0this is bogus%d",1); // expected-warning {{string contains '\0'}}
211 snprintf(b,10,"%%%%%d\0%d",1,2); // expected-warning {{string contains '\0'}}
212 printf("%\0d",1); // expected-warning {{string contains '\0'}}
213 }
214
check_empty_format_string(char * buf,...)215 void check_empty_format_string(char* buf, ...)
216 {
217 va_list ap;
218 va_start(ap,buf);
219 vprintf("",ap); // expected-warning {{format string is empty}}
220 sprintf(buf, "", 1); // expected-warning {{format string is empty}}
221
222 // Don't warn about empty format strings when there are no data arguments.
223 // This can arise from macro expansions and non-standard format string
224 // functions.
225 sprintf(buf, ""); // no-warning
226 }
227
check_wide_string(char * b,...)228 void check_wide_string(char* b, ...)
229 {
230 va_list ap;
231 va_start(ap,b);
232
233 printf(L"foo %d",2); // expected-warning {{incompatible pointer types}}, expected-warning {{should not be a wide string}}
234 vsprintf(b,L"bar %d",ap); // expected-warning {{incompatible pointer types}}, expected-warning {{should not be a wide string}}
235 }
236
check_asterisk_precision_width(int x)237 void check_asterisk_precision_width(int x) {
238 printf("%*d"); // expected-warning {{'*' specified field width is missing a matching 'int' argument}}
239 printf("%.*d"); // expected-warning {{'.*' specified field precision is missing a matching 'int' argument}}
240 printf("%*d",12,x); // no-warning
241 printf("%*d","foo",x); // expected-warning {{field width should have type 'int', but argument has type 'char *'}}
242 printf("%.*d","foo",x); // expected-warning {{field precision should have type 'int', but argument has type 'char *'}}
243 }
244
245 void __attribute__((format(printf,1,3))) myprintf(const char*, int blah, ...);
246
test_myprintf(void)247 void test_myprintf(void) {
248 myprintf("%d", 17, 18); // okay
249 }
250
test_constant_bindings(void)251 void test_constant_bindings(void) {
252 const char * const s1 = "hello";
253 const char s2[] = "hello";
254 const char *s3 = "hello";
255 char * const s4 = "hello";
256 extern const char s5[];
257
258 printf(s1); // no-warning
259 printf(s2); // no-warning
260 printf(s3); // expected-warning{{not a string literal}}
261 // expected-note@-1{{treat the string as an argument to avoid this}}
262 printf(s4); // expected-warning{{not a string literal}}
263 // expected-note@-1{{treat the string as an argument to avoid this}}
264 printf(s5); // expected-warning{{not a string literal}}
265 // expected-note@-1{{treat the string as an argument to avoid this}}
266 }
267
268
269 // Test what happens when -Wformat-security only.
270 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
271 #pragma GCC diagnostic warning "-Wformat-security"
272
test9(char * P)273 void test9(char *P) {
274 int x;
275 printf(P); // expected-warning {{format string is not a string literal (potentially insecure)}}
276 // expected-note@-1{{treat the string as an argument to avoid this}}
277 printf(P, 42);
278 }
279
torture(va_list v8)280 void torture(va_list v8) {
281 vprintf ("%*.*d", v8); // no-warning
282
283 }
284
test10(int x,float f,int i,long long lli)285 void test10(int x, float f, int i, long long lli) {
286 printf("%s"); // expected-warning{{more '%' conversions than data arguments}}
287 printf("%@", 12); // expected-warning{{invalid conversion specifier '@'}}
288 printf("\0"); // expected-warning{{format string contains '\0' within the string body}}
289 printf("xs\0"); // expected-warning{{format string contains '\0' within the string body}}
290 printf("%*d\n"); // expected-warning{{'*' specified field width is missing a matching 'int' argument}}
291 printf("%*.*d\n", x); // expected-warning{{'.*' specified field precision is missing a matching 'int' argument}}
292 printf("%*d\n", f, x); // expected-warning{{field width should have type 'int', but argument has type 'double'}}
293 printf("%*.*d\n", x, f, x); // expected-warning{{field precision should have type 'int', but argument has type 'double'}}
294 printf("%**\n"); // expected-warning{{invalid conversion specifier '*'}}
295 printf("%d%d\n", x); // expected-warning{{more '%' conversions than data arguments}}
296 printf("%d\n", x, x); // expected-warning{{data argument not used by format string}}
297 printf("%W%d\n", x, x); // expected-warning{{invalid conversion specifier 'W'}} expected-warning {{data argument not used by format string}}
298 printf("%"); // expected-warning{{incomplete format specifier}}
299 printf("%.d", x); // no-warning
300 printf("%.", x); // expected-warning{{incomplete format specifier}}
301 printf("%f", 4); // expected-warning{{format specifies type 'double' but the argument has type 'int'}}
302 printf("%qd", lli); // no-warning
303 printf("%qd", x); // expected-warning{{format specifies type 'long long' but the argument has type 'int'}}
304 printf("%qp", (void *)0); // expected-warning{{length modifier 'q' results in undefined behavior or no effect with 'p' conversion specifier}}
305 printf("hhX %hhX", (unsigned char)10); // no-warning
306 printf("llX %llX", (long long) 10); // no-warning
307 printf("%lb %lB", (long) 10, (long) 10); // no-warning
308 printf("%llb %llB", (long long) 10, (long long) 10); // no-warning
309 // This is fine, because there is an implicit conversion to an int.
310 printf("%d", (unsigned char) 10); // no-warning
311 printf("%d", (long long) 10); // expected-warning{{format specifies type 'int' but the argument has type 'long long'}}
312 printf("%Lf\n", (long double) 1.0); // no-warning
313 printf("%f\n", (long double) 1.0); // expected-warning{{format specifies type 'double' but the argument has type 'long double'}}
314 // The man page says that a zero precision is okay.
315 printf("%.0Lf", (long double) 1.0); // no-warning
316 printf("%c\n", "x"); // expected-warning{{format specifies type 'int' but the argument has type 'char *'}}
317 printf("%c\n", 1.23); // expected-warning{{format specifies type 'int' but the argument has type 'double'}}
318 printf("Format %d, is %! %f", 1, 4.4); // expected-warning{{invalid conversion specifier '!'}}
319 }
320
321 typedef unsigned char uint8_t;
322
should_understand_small_integers(void)323 void should_understand_small_integers(void) {
324 printf("%hhu", (short) 10); // expected-warning{{format specifies type 'unsigned char' but the argument has type 'short'}}
325 printf("%hu\n", (unsigned char)1); // warning with -Wformat-pedantic only
326 printf("%hu\n", (uint8_t)1); // warning with -Wformat-pedantic only
327 }
328
test11(void * p,char * s)329 void test11(void *p, char *s) {
330 printf("%p", p); // no-warning
331 printf("%p", 123); // expected-warning{{format specifies type 'void *' but the argument has type 'int'}}
332 printf("%.4p", p); // expected-warning{{precision used with 'p' conversion specifier, resulting in undefined behavior}}
333 printf("%+p", p); // expected-warning{{flag '+' results in undefined behavior with 'p' conversion specifier}}
334 printf("% p", p); // expected-warning{{flag ' ' results in undefined behavior with 'p' conversion specifier}}
335 printf("%0p", p); // expected-warning{{flag '0' results in undefined behavior with 'p' conversion specifier}}
336 printf("%s", s); // no-warning
337 printf("%+s", p); // expected-warning{{flag '+' results in undefined behavior with 's' conversion specifier}}
338 // expected-warning@-1 {{format specifies type 'char *' but the argument has type 'void *'}}
339 printf("% s", p); // expected-warning{{flag ' ' results in undefined behavior with 's' conversion specifier}}
340 // expected-warning@-1 {{format specifies type 'char *' but the argument has type 'void *'}}
341 printf("%0s", p); // expected-warning{{flag '0' results in undefined behavior with 's' conversion specifier}}
342 // expected-warning@-1 {{format specifies type 'char *' but the argument has type 'void *'}}
343 }
344
test12(char * b)345 void test12(char *b) {
346 unsigned char buf[4];
347 printf ("%.4s\n", buf); // no-warning
348 printf ("%.4s\n", &buf); // expected-warning{{format specifies type 'char *' but the argument has type 'unsigned char (*)[4]'}}
349
350 // Verify that we are checking asprintf
351 asprintf(&b, "%d", "asprintf"); // expected-warning{{format specifies type 'int' but the argument has type 'char *'}}
352 }
353
test13(short x)354 void test13(short x) {
355 char bel = 007;
356 printf("bel: '0%hhd'\n", bel); // no-warning
357 printf("x: '0%hhd'\n", x); // expected-warning {{format specifies type 'char' but the argument has type 'short'}}
358 }
359
360 typedef struct __aslclient *aslclient;
361 typedef struct __aslmsg *aslmsg;
362 int asl_log(aslclient asl, aslmsg msg, int level, const char *format, ...) __attribute__((__format__ (__printf__, 4, 5)));
test_asl(aslclient asl)363 void test_asl(aslclient asl) {
364 asl_log(asl, 0, 3, "Error: %m"); // no-warning
365 asl_log(asl, 0, 3, "Error: %W"); // expected-warning{{invalid conversion specifier 'W'}}
366 }
367
368 typedef enum { A } int_t;
f0(int_t x)369 void f0(int_t x) { printf("%d\n", x); }
370
371 // Unicode test cases. These are possibly specific to Mac OS X. If so, they should
372 // eventually be moved into a separate test.
373
test_unicode_conversions(wchar_t * s)374 void test_unicode_conversions(wchar_t *s) {
375 printf("%S", s); // no-warning
376 printf("%s", s); // expected-warning{{format specifies type 'char *' but the argument has type 'wchar_t *'}}
377 printf("%C", s[0]); // no-warning
378 #if defined(__sun) && !defined(__LP64__)
379 printf("%c", s[0]); // expected-warning{{format specifies type 'int' but the argument has type 'wchar_t' (aka 'long')}}
380 #else
381 printf("%c", s[0]);
382 #endif
383 // FIXME: This test reports inconsistent results. On Windows, '%C' expects
384 // 'unsigned short'.
385 // printf("%C", 10);
386 printf("%S", "hello"); // expected-warning{{but the argument has type 'char *'}}
387 }
388
389 // Mac OS X supports positional arguments in format strings.
390 // This is an IEEE extension (IEEE Std 1003.1).
391 // FIXME: This is probably not portable everywhere.
test_positional_arguments(void)392 void test_positional_arguments(void) {
393 printf("%0$", (int)2); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
394 printf("%1$*0$d", (int) 2); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
395 printf("%1$d", (int) 2); // no-warning
396 printf("%1$d", (int) 2, 2); // expected-warning{{data argument not used by format string}}
397 printf("%1$d%1$f", (int) 2); // expected-warning{{format specifies type 'double' but the argument has type 'int'}}
398 printf("%1$2.2d", (int) 2); // no-warning
399 printf("%2$*1$.2d", (int) 2, (int) 3); // no-warning
400 printf("%2$*8$d", (int) 2, (int) 3); // expected-warning{{specified field width is missing a matching 'int' argument}}
401 printf("%%%1$d", (int) 2); // no-warning
402 printf("%1$d%%", (int) 2); // no-warning
403 }
404
405 // PR 6697 - Handle format strings where the data argument is not adjacent to the format string
406 void myprintf_PR_6697(const char *format, int x, ...) __attribute__((__format__(printf,1, 3)));
test_pr_6697(void)407 void test_pr_6697(void) {
408 myprintf_PR_6697("%s\n", 1, "foo"); // no-warning
409 myprintf_PR_6697("%s\n", 1, (int)0); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
410 // FIXME: Not everything should clearly support positional arguments,
411 // but we need a way to identify those cases.
412 myprintf_PR_6697("%1$s\n", 1, "foo"); // no-warning
413 myprintf_PR_6697("%2$s\n", 1, "foo"); // expected-warning{{data argument position '2' exceeds the number of data arguments (1)}}
414 myprintf_PR_6697("%18$s\n", 1, "foo"); // expected-warning{{data argument position '18' exceeds the number of data arguments (1)}}
415 myprintf_PR_6697("%1$s\n", 1, (int) 0); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
416 }
417
rdar8026030(FILE * fp)418 void rdar8026030(FILE *fp) {
419 fprintf(fp, "\%"); // expected-warning{{incomplete format specifier}}
420 }
421
bug7377_bad_length_mod_usage(void)422 void bug7377_bad_length_mod_usage(void) {
423 // Bad length modifiers
424 printf("%hhs", "foo"); // expected-warning{{length modifier 'hh' results in undefined behavior or no effect with 's' conversion specifier}}
425 printf("%1$zp", (void *)0); // expected-warning{{length modifier 'z' results in undefined behavior or no effect with 'p' conversion specifier}}
426 printf("%ls", L"foo"); // no-warning
427 printf("%#.2Lf", (long double)1.234); // no-warning
428
429 // Bad flag usage
430 printf("%#p", (void *) 0); // expected-warning{{flag '#' results in undefined behavior with 'p' conversion specifier}}
431 printf("%0d", -1); // no-warning
432 printf("%0b%0B", -1u, -1u); // no-warning
433 printf("%-p", (void *) 0); // no-warning
434 #if !defined(__ANDROID__) && !defined(__Fuchsia__)
435 printf("%#n", (int *) 0); // expected-warning{{flag '#' results in undefined behavior with 'n' conversion specifier}}
436 printf("%-n", (int *) 0); // expected-warning{{flag '-' results in undefined behavior with 'n' conversion specifier}}
437 #else
438 printf("%#n", (int *) 0); // expected-warning{{flag '#' results in undefined behavior with 'n' conversion specifier}}
439 // expected-warning@-1 {{'%n' specifier not supported on this platform}}
440 printf("%-n", (int *) 0); // expected-warning{{flag '-' results in undefined behavior with 'n' conversion specifier}}
441 // expected-warning@-1 {{'%n' specifier not supported on this platform}}
442 #endif // !defined(__ANDROID__) && !defined(__Fuchsia__)
443
444 // Bad optional amount use
445 printf("%.2c", 'a'); // expected-warning{{precision used with 'c' conversion specifier, resulting in undefined behavior}}
446 #if !defined(__ANDROID__) && !defined(__Fuchsia__)
447 printf("%1n", (int *) 0); // expected-warning{{field width used with 'n' conversion specifier, resulting in undefined behavior}}
448 printf("%.9n", (int *) 0); // expected-warning{{precision used with 'n' conversion specifier, resulting in undefined behavior}}
449 #else
450 printf("%1n", (int *) 0); // expected-warning{{field width used with 'n' conversion specifier, resulting in undefined behavior}}
451 // expected-warning@-1 {{'%n' specifier not supported on this platform}}
452 printf("%.9n", (int *) 0); // expected-warning{{precision used with 'n' conversion specifier, resulting in undefined behavior}}
453 // expected-warning@-1 {{'%n' specifier not supported on this platform}}
454 #endif // #if !defined(__ANDROID__) && !defined(__Fuchsia__)
455
456 // Ignored flags
457 printf("% +f", 1.23); // expected-warning{{flag ' ' is ignored when flag '+' is present}}
458 printf("%+ f", 1.23); // expected-warning{{flag ' ' is ignored when flag '+' is present}}
459 printf("%0-f", 1.23); // expected-warning{{flag '0' is ignored when flag '-' is present}}
460 printf("%-0f", 1.23); // expected-warning{{flag '0' is ignored when flag '-' is present}}
461 printf("%-+f", 1.23); // no-warning
462 }
463
464 // PR 7981 - handle '%lc' (wint_t)
465
pr7981(wint_t c,wchar_t c2)466 void pr7981(wint_t c, wchar_t c2) {
467 printf("%lc", c); // no-warning
468 printf("%lc", 1.0); // expected-warning{{the argument has type 'double'}}
469 #if __WINT_WIDTH__ == 32 && !(defined(__sun) && !defined(__LP64__))
470 printf("%lc", (char) 1); // no-warning
471 #else
472 printf("%lc", (char) 1); // expected-warning{{the argument has type 'char'}}
473 #endif
474 printf("%lc", &c); // expected-warning{{the argument has type 'wint_t *'}}
475 // If wint_t and wchar_t are the same width and wint_t is signed where
476 // wchar_t is unsigned, an implicit conversion isn't possible.
477 #if defined(__WINT_UNSIGNED__) || !defined(__WCHAR_UNSIGNED__) || \
478 __WINT_WIDTH__ > __WCHAR_WIDTH__
479 printf("%lc", c2); // no-warning
480 #endif
481 }
482
483 // -Wformat-security says NULL is not a string literal
rdar8269537(void)484 void rdar8269537(void) {
485 // This is likely to crash in most cases, but -Wformat-nonliteral technically
486 // doesn't warn in this case.
487 printf(0); // no-warning
488 }
489
490 // Handle functions with multiple format attributes.
491 extern void rdar8332221_vprintf_scanf(const char *, va_list, const char *, ...)
492 __attribute__((__format__(__printf__, 1, 0)))
493 __attribute__((__format__(__scanf__, 3, 4)));
494
rdar8332221(va_list ap,int * x,long * y)495 void rdar8332221(va_list ap, int *x, long *y) {
496 rdar8332221_vprintf_scanf("%", ap, "%d", x); // expected-warning{{incomplete format specifier}}
497 }
498
499 // PR8641
pr8641(void)500 void pr8641(void) {
501 printf("%#x\n", 10);
502 printf("%#X\n", 10);
503 printf("%#b %#15.8B\n", 10, 10u);
504 }
505
posix_extensions(void)506 void posix_extensions(void) {
507 // Test %'d, "thousands grouping".
508 printf("%'d\n", 123456789); // no-warning
509 printf("%'i\n", 123456789); // no-warning
510 printf("%'f\n", (float) 1.0); // no-warning
511 printf("%'p\n", (void*) 0); // expected-warning{{results in undefined behavior with 'p' conversion specifier}}
512 printf("%'b\n", 123456789); // expected-warning{{results in undefined behavior with 'b' conversion specifier}}
513 printf("%'B\n", 123456789); // expected-warning{{results in undefined behavior with 'B' conversion specifier}}
514 }
515
516 // PR8486
517 //
518 // Test what happens when -Wformat is on, but -Wformat-security is off.
519 #pragma GCC diagnostic warning "-Wformat"
520 #pragma GCC diagnostic ignored "-Wformat-security"
521
pr8486(void)522 void pr8486(void) {
523 printf("%s", 1); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
524 }
525
526 // PR9314
527 // Don't warn about string literals that are PreDefinedExprs, e.g. __func__.
pr9314(void)528 void pr9314(void) {
529 printf(__PRETTY_FUNCTION__); // no-warning
530 printf(__func__); // no-warning
531 }
532
533 int printf(const char * restrict, ...) __attribute__((__format__ (__printf__, 1, 2)));
534
rdar9612060(void)535 void rdar9612060(void) {
536 printf("%s", 2); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
537 }
538
check_char(unsigned char x,signed char y)539 void check_char(unsigned char x, signed char y) {
540 printf("%c", y); // no-warning
541 printf("%hhu", x); // no-warning
542 printf("%hhi", y); // no-warning
543 printf("%hhi", x); // no-warning
544 printf("%c", x); // no-warning
545 printf("%hhu", y); // no-warning
546 printf("%hhb %hhB", x, x); // no-warning
547 }
548
549 // Test suppression of individual warnings.
550
test_suppress_invalid_specifier(void)551 void test_suppress_invalid_specifier(void) {
552 #pragma clang diagnostic push
553 #pragma clang diagnostic ignored "-Wformat-invalid-specifier"
554 printf("%@", 12); // no-warning
555 #pragma clang diagnostic pop
556 }
557
558 // Make sure warnings are on for next test.
559 #pragma GCC diagnostic warning "-Wformat"
560 #pragma GCC diagnostic warning "-Wformat-security"
561
562 // Test that the printf call site is where the warning is attached. If the
563 // format string is somewhere else, point to it in a note.
pr9751(void)564 void pr9751(void) {
565 const char kFormat1[] = "%d %d \n"; // expected-note{{format string is defined here}}}
566 printf(kFormat1, 0); // expected-warning{{more '%' conversions than data arguments}}
567 printf("%d %s\n", 0); // expected-warning{{more '%' conversions than data arguments}}
568
569 const char kFormat2[] = "%18$s\n"; // expected-note{{format string is defined here}}
570 printf(kFormat2, 1, "foo"); // expected-warning{{data argument position '18' exceeds the number of data arguments (2)}}
571 printf("%18$s\n", 1, "foo"); // expected-warning{{data argument position '18' exceeds the number of data arguments (2)}}
572
573 const char kFormat4[] = "%y"; // expected-note{{format string is defined here}}
574 printf(kFormat4, 5); // expected-warning{{invalid conversion specifier 'y'}}
575 printf("%y", 5); // expected-warning{{invalid conversion specifier 'y'}}
576
577 const char kFormat5[] = "%."; // expected-note{{format string is defined here}}
578 printf(kFormat5, 5); // expected-warning{{incomplete format specifier}}
579 printf("%.", 5); // expected-warning{{incomplete format specifier}}
580
581 const char kFormat6[] = "%s"; // expected-note{{format string is defined here}}
582 printf(kFormat6, 5); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
583 printf("%s", 5); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
584
585 const char kFormat7[] = "%0$"; // expected-note{{format string is defined here}}
586 printf(kFormat7, 5); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
587 printf("%0$", 5); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
588
589 const char kFormat8[] = "%1$d %d"; // expected-note{{format string is defined here}}
590 printf(kFormat8, 4, 4); // expected-warning{{cannot mix positional and non-positional arguments in format string}}
591 printf("%1$d %d", 4, 4); // expected-warning{{cannot mix positional and non-positional arguments in format string}}
592
593 const char kFormat9[] = ""; // expected-note{{format string is defined here}}
594 printf(kFormat9, 4, 4); // expected-warning{{format string is empty}}
595 printf("", 4, 4); // expected-warning{{format string is empty}}
596
597 const char kFormat10[] = "\0%d"; // expected-note{{format string is defined here}}
598 printf(kFormat10, 4); // expected-warning{{format string contains '\0' within the string body}}
599 printf("\0%d", 4); // expected-warning{{format string contains '\0' within the string body}}
600
601 const char kFormat11[] = "%*d"; // expected-note{{format string is defined here}}
602 printf(kFormat11); // expected-warning{{'*' specified field width is missing a matching 'int' argument}}
603 printf("%*d"); // expected-warning{{'*' specified field width is missing a matching 'int' argument}}
604
605 const char kFormat12[] = "%*d"; // expected-note{{format string is defined here}}
606 printf(kFormat12, 4.4); // expected-warning{{field width should have type 'int', but argument has type 'double'}}
607 printf("%*d", 4.4); // expected-warning{{field width should have type 'int', but argument has type 'double'}}
608
609 const char kFormat13[] = "%.3p"; // expected-note{{format string is defined here}}
610 void *p;
611 printf(kFormat13, p); // expected-warning{{precision used with 'p' conversion specifier, resulting in undefined behavior}}
612 printf("%.3p", p); // expected-warning{{precision used with 'p' conversion specifier, resulting in undefined behavior}}
613
614 const char kFormat14[] = "%0s"; // expected-note{{format string is defined here}}
615 printf(kFormat14, "a"); // expected-warning{{flag '0' results in undefined behavior with 's' conversion specifier}}
616 printf("%0s", "a"); // expected-warning{{flag '0' results in undefined behavior with 's' conversion specifier}}
617
618 const char kFormat15[] = "%hhs"; // expected-note{{format string is defined here}}
619 printf(kFormat15, "a"); // expected-warning{{length modifier 'hh' results in undefined behavior or no effect with 's' conversion specifier}}
620 printf("%hhs", "a"); // expected-warning{{length modifier 'hh' results in undefined behavior or no effect with 's' conversion specifier}}
621
622 const char kFormat16[] = "%-0d"; // expected-note{{format string is defined here}}
623 printf(kFormat16, 5); // expected-warning{{flag '0' is ignored when flag '-' is present}}
624 printf("%-0d", 5); // expected-warning{{flag '0' is ignored when flag '-' is present}}
625
626 // Make sure that the "format string is defined here" note is not emitted
627 // when the original string is within the argument expression.
628 printf(1 ? "yes %d" : "no %d"); // expected-warning{{more '%' conversions than data arguments}}
629
630 const char kFormat17[] = "%hu"; // expected-note{{format string is defined here}}}
631 printf(kFormat17, (int[]){0}); // expected-warning{{format specifies type 'unsigned short' but the argument}}
632
633 printf("%a", (long double)0); // expected-warning{{format specifies type 'double' but the argument has type 'long double'}}
634
635 // Test braced char[] initializers.
636 const char kFormat18[] = { "%lld" }; // expected-note{{format string is defined here}}
637 printf(kFormat18, 0); // expected-warning{{format specifies type}}
638
639 // Make sure we point at the offending argument rather than the format string.
640 const char kFormat19[] = "%d"; // expected-note{{format string is defined here}}
641 printf(kFormat19,
642 0.0); // expected-warning{{format specifies}}
643 }
644
pr18905(void)645 void pr18905(void) {
646 const char s1[] = "s\0%s"; // expected-note{{format string is defined here}}
647 const char s2[1] = "s"; // expected-note{{format string is defined here}}
648 const char s3[2] = "s\0%s"; // expected-warning{{initializer-string for char array is too long}}
649 const char s4[10] = "s";
650 const char s5[0] = "%s"; // expected-warning{{initializer-string for char array is too long}}
651 // expected-note@-1{{format string is defined here}}
652
653 printf(s1); // expected-warning{{format string contains '\0' within the string body}}
654 printf(s2); // expected-warning{{format string is not null-terminated}}
655 printf(s3); // no-warning
656 printf(s4); // no-warning
657 printf(s5); // expected-warning{{format string is not null-terminated}}
658 }
659
660 void __attribute__((format(strfmon,1,2))) monformat(const char *fmt, ...);
661 void __attribute__((format(strftime,1,0))) dateformat(const char *fmt);
662
663 // Other formats
test_other_formats(void)664 void test_other_formats(void) {
665 char *str = "";
666 monformat("", 1); // expected-warning{{format string is empty}}
667 monformat(str); // expected-warning{{format string is not a string literal (potentially insecure)}}
668 dateformat(""); // expected-warning{{format string is empty}}
669 dateformat(str); // no-warning (using strftime non-literal is not unsafe)
670 }
671
672 // Do not warn about unused arguments coming from system headers.
673 #include <format-unused-system-args.h>
test_unused_system_args(int x)674 void test_unused_system_args(int x) {
675 PRINT1("%d\n", x); // no-warning{{extra argument is system header is OK}}
676 }
677
pr12761(char c)678 void pr12761(char c) {
679 // This should not warn even with -fno-signed-char.
680 printf("%hhx", c);
681 }
682
test_opencl_vector_format(int x)683 void test_opencl_vector_format(int x) {
684 printf("%v4d", x); // expected-warning{{invalid conversion specifier 'v'}}
685 printf("%vd", x); // expected-warning{{invalid conversion specifier 'v'}}
686 printf("%0vd", x); // expected-warning{{invalid conversion specifier 'v'}}
687 printf("%hlf", x); // expected-warning{{invalid conversion specifier 'l'}}
688 printf("%hld", x); // expected-warning{{invalid conversion specifier 'l'}}
689 }
690
691 // Test that we correctly merge the format in both orders.
692 extern void test14_foo(const char *, const char *, ...)
693 __attribute__((__format__(__printf__, 1, 3)));
694 extern void test14_foo(const char *, const char *, ...)
695 __attribute__((__format__(__scanf__, 2, 3)));
696
697 extern void test14_bar(const char *, const char *, ...)
698 __attribute__((__format__(__scanf__, 2, 3)));
699 extern void test14_bar(const char *, const char *, ...)
700 __attribute__((__format__(__printf__, 1, 3)));
701
test14_zed(int * p)702 void test14_zed(int *p) {
703 test14_foo("%", "%d", p); // expected-warning{{incomplete format specifier}}
704 test14_bar("%", "%d", p); // expected-warning{{incomplete format specifier}}
705 }
706
707 #if !defined(__ANDROID__) && !defined(__Fuchsia__)
708
test_qualifiers(volatile int * vip,const int * cip,const volatile int * cvip)709 void test_qualifiers(volatile int *vip, const int *cip,
710 const volatile int *cvip) {
711 printf("%n", cip); // expected-warning{{format specifies type 'int *' but the argument has type 'const int *'}}
712 printf("%n", cvip); // expected-warning{{format specifies type 'int *' but the argument has type 'const volatile int *'}}
713
714 printf("%n", vip); // No warning.
715 printf("%p", cip); // No warning.
716 printf("%p", cvip); // No warning.
717
718
719 typedef int* ip_t;
720 typedef const int* cip_t;
721 printf("%n", (ip_t)0); // No warning.
722 printf("%n", (cip_t)0); // expected-warning{{format specifies type 'int *' but the argument has type 'cip_t' (aka 'const int *')}}
723 }
724
725 #else
726
test_qualifiers(volatile int * vip,const int * cip,const volatile int * cvip)727 void test_qualifiers(volatile int *vip, const int *cip,
728 const volatile int *cvip) {
729 printf("%n", cip); // expected-warning{{format specifies type 'int *' but the argument has type 'const int *'}}
730 // expected-warning@-1 {{'%n' specifier not supported on this platform}}
731 printf("%n", cvip); // expected-warning{{format specifies type 'int *' but the argument has type 'const volatile int *'}}
732 // expected-warning@-1 {{'%n' specifier not supported on this platform}}
733
734 printf("%n", vip); // expected-warning{{'%n' specifier not supported on this platform}}
735 printf("%p", cip); // No warning.
736 printf("%p", cvip); // No warning.
737
738
739 typedef int* ip_t;
740 typedef const int* cip_t;
741 printf("%n", (ip_t)0); // expected-warning{{'%n' specifier not supported on this platform}}
742 printf("%n", (cip_t)0); // expected-warning{{format specifies type 'int *' but the argument has type 'cip_t' (aka 'const int *')}}
743 // expected-warning@-1 {{'%n' specifier not supported on this platform}}
744 }
745
746 #endif // #if !defined(__ANDROID__) && !defined(__Fuchsia__)
747
748 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
749 #pragma GCC diagnostic warning "-Wformat-security"
750 extern void test_format_security_extra_args(const char*, int, ...)
751 __attribute__((__format__(__printf__, 1, 3)));
test_format_security_pos(char * string)752 void test_format_security_pos(char* string) {
753 test_format_security_extra_args(string, 5); // expected-warning {{format string is not a string literal (potentially insecure)}}
754 // expected-note@-1{{treat the string as an argument to avoid this}}
755 }
756 #pragma GCC diagnostic warning "-Wformat-nonliteral"
757
test_char_pointer_arithmetic(int b)758 void test_char_pointer_arithmetic(int b) {
759 const char s1[] = "string";
760 const char s2[] = "%s string";
761
762 printf(s1 - 1); // expected-warning {{format string is not a string literal (potentially insecure)}}
763 // expected-note@-1{{treat the string as an argument to avoid this}}
764
765 printf(s1 + 2); // no-warning
766 printf(s2 + 2); // no-warning
767
768 const char s3[] = "%s string";
769 printf((s3 + 2) - 2); // expected-warning{{more '%' conversions than data arguments}}
770 // expected-note@-2{{format string is defined here}}
771 printf(2 + s2); // no-warning
772 printf(6 + s2 - 2); // no-warning
773 printf(2 + (b ? s1 : s2)); // no-warning
774
775 const char s5[] = "string %s";
776 printf(2 + (b ? s2 : s5)); // expected-warning{{more '%' conversions than data arguments}}
777 // expected-note@-2{{format string is defined here}}
778 printf(2 + (b ? s2 : s5), ""); // no-warning
779 printf(2 + (b ? s1 : s2 - 2), ""); // no-warning
780
781 const char s6[] = "%s string";
782 printf(2 + (b ? s1 : s6 - 2)); // expected-warning{{more '%' conversions than data arguments}}
783 // expected-note@-2{{format string is defined here}}
784 printf(1 ? s2 + 2 : s2); // no-warning
785 printf(0 ? s2 : s2 + 2); // no-warning
786 printf(2 + s2 + 5 * 3 - 16, ""); // expected-warning{{data argument not used}}
787
788 const char s7[] = "%s string %s %s";
789 printf(s7 + 3, ""); // expected-warning{{more '%' conversions than data arguments}}
790 // expected-note@-2{{format string is defined here}}
791 }
792
PR30481(void)793 void PR30481(void) {
794 // This caused crashes due to invalid casts.
795 printf(1 > 0); // expected-warning{{format string is not a string literal}} expected-error{{incompatible integer to pointer conversion}} expected-note@format-strings.c:*{{passing argument to parameter here}} expected-note{{to avoid this}}
796 }
797
test_printf_opaque_ptr(void * op)798 void test_printf_opaque_ptr(void *op) {
799 printf("%s", op); // expected-warning{{format specifies type 'char *' but the argument has type 'void *'}}
800 }
801
test_block(void)802 void test_block(void) {
803 void __attribute__((__format__(__printf__, 1, 2))) (^printf_arg1)(
804 const char *, ...) =
805 ^(const char *fmt, ...) __attribute__((__format__(__printf__, 1, 2))) {
806 va_list ap;
807 va_start(ap, fmt);
808 vprintf(fmt, ap);
809 va_end(ap);
810 };
811
812 printf_arg1("%s string %i\n", "aaa", 123);
813 printf_arg1("%s string\n", 123); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
814
815 void __attribute__((__format__(__printf__, 2, 3))) (^printf_arg2)(
816 const char *, const char *, ...) =
817 ^(const char *not_fmt, const char *fmt, ...)
818 __attribute__((__format__(__printf__, 2, 3))) {
819 va_list ap;
820 va_start(ap, fmt);
821 vprintf(fmt, ap);
822 vprintf(not_fmt, ap); // expected-warning{{format string is not a string literal}}
823 va_end(ap);
824 };
825
826 printf_arg2("foo", "%s string %i\n", "aaa", 123);
827 printf_arg2("%s string\n", "foo", "bar"); // expected-warning{{data argument not used by format string}}
828 }
829
test_promotion(void)830 void test_promotion(void) {
831 // Default argument promotions for *printf in N2562
832 // https://github.com/llvm/llvm-project/issues/57102
833 // N2562: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2562.pdf
834 int i;
835 signed char sc;
836 unsigned char uc;
837 char c;
838 short ss;
839 unsigned short us;
840
841 printf("%hhd %hd %d %hhd %hd %d", i, i, i, sc, sc, sc); // no-warning
842 printf("%hhd %hd %d %hhd %hd %d", uc, uc, uc, c, c, c); // no-warning
843
844 // %ld %lld %llx
845 printf("%ld", i); // expected-warning{{format specifies type 'long' but the argument has type 'int'}}
846 printf("%lld", i); // expected-warning{{format specifies type 'long long' but the argument has type 'int'}}
847 printf("%ld", sc); // expected-warning{{format specifies type 'long' but the argument has type 'signed char'}}
848 printf("%lld", sc); // expected-warning{{format specifies type 'long long' but the argument has type 'signed char'}}
849 printf("%ld", uc); // expected-warning{{format specifies type 'long' but the argument has type 'unsigned char'}}
850 printf("%lld", uc); // expected-warning{{format specifies type 'long long' but the argument has type 'unsigned char'}}
851 printf("%llx", i); // expected-warning{{format specifies type 'unsigned long long' but the argument has type 'int'}}
852
853 // ill formed spec for floats
854 printf("%hf", // expected-warning{{length modifier 'h' results in undefined behavior or no effect with 'f' conversion specifier}}
855 sc); // expected-warning{{format specifies type 'double' but the argument has type 'signed char'}}
856
857 // for %hhd and `short` they are compatible by promotions but more likely misuse
858 printf("%hd", ss); // no-warning
859 printf("%hhd", ss); // expected-warning{{format specifies type 'char' but the argument has type 'short'}}
860 printf("%hu", us); // no-warning
861 printf("%hhu", ss); // expected-warning{{format specifies type 'unsigned char' but the argument has type 'short'}}
862
863 // floats & integers are not compatible
864 printf("%f", i); // expected-warning{{format specifies type 'double' but the argument has type 'int'}}
865 printf("%f", sc); // expected-warning{{format specifies type 'double' but the argument has type 'signed char'}}
866 printf("%f", uc); // expected-warning{{format specifies type 'double' but the argument has type 'unsigned char'}}
867 printf("%f", c); // expected-warning{{format specifies type 'double' but the argument has type 'char'}}
868 printf("%f", ss); // expected-warning{{format specifies type 'double' but the argument has type 'short'}}
869 printf("%f", us); // expected-warning{{format specifies type 'double' but the argument has type 'unsigned short'}}
870
871 // character literals
872 // In C language engineering practice, printing a character literal with %hhd or %d is common, but %hd may be misuse.
873 printf("%hhu", 'a'); // no-warning
874 printf("%hhd", 'a'); // no-warning
875 printf("%hd", 'a'); // expected-warning{{format specifies type 'short' but the argument has type 'char'}}
876 printf("%hu", 'a'); // expected-warning{{format specifies type 'unsigned short' but the argument has type 'char'}}
877 printf("%d", 'a'); // no-warning
878 printf("%u", 'a'); // no-warning
879
880 // pointers
881 printf("%s", i); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
882 }
883