* [PATCH] C/C++: add hints for strerror
@ 2023-10-02 2:14 Oskari Pirhonen
0 siblings, 0 replies; only message in thread
From: Oskari Pirhonen @ 2023-10-02 2:14 UTC (permalink / raw)
To: gcc-patches
Add proper hints for implicit declaration of strerror.
The results could be confusing depending on the other included headers.
These example messages are from compiling a trivial program to print the
string for an errno value. It only includes stdio.h (cstdio for C++).
Before:
$ /tmp/gcc-master/bin/gcc test.c -o test_c
test.c: In function ‘main’:
test.c:4:20: warning: implicit declaration of function ‘strerror’; did you mean ‘perror’? [-Wimplicit-function-declaration]
4 | printf("%s\n", strerror(0));
| ^~~~~~~~
| perror
$ /tmp/gcc-master/bin/g++ test.cpp -o test_cpp
test.cpp: In function ‘int main()’:
test.cpp:4:20: error: ‘strerror’ was not declared in this scope; did you mean ‘stderr’?
4 | printf("%s\n", strerror(0));
| ^~~~~~~~
| stderr
After:
$ /tmp/gcc-known-headers/bin/gcc test.c -o test_c
test.c: In function ‘main’:
test.c:4:20: warning: implicit declaration of function ‘strerror’ [-Wimplicit-function-declaration]
4 | printf("%s\n", strerror(0));
| ^~~~~~~~
test.c:2:1: note: ‘strerror’ is defined in header ‘<string.h>’; this is probably fixable by adding ‘#include <string.h>’
1 | #include <stdio.h>
+++ |+#include <string.h>
2 |
$ /tmp/gcc-known-headers/bin/g++ test.cpp -o test_cpp
test.cpp: In function ‘int main()’:
test.cpp:4:20: error: ‘strerror’ was not declared in this scope
4 | printf("%s\n", strerror(0));
| ^~~~~~~~
test.cpp:2:1: note: ‘strerror’ is defined in header ‘<cstring>’; this is probably fixable by adding ‘#include <cstring>’
1 | #include <cstdio>
+++ |+#include <cstring>
2 |
gcc/c-family/ChangeLog:
* known-headers.cc (get_stdlib_header_for_name): Add strerror.
gcc/testsuite/ChangeLog:
* g++.dg/spellcheck-stdlib.C: Add check for strerror.
* gcc.dg/spellcheck-stdlib-2.c: New test.
Signed-off-by: Oskari Pirhonen <xxc3ncoredxx@gmail.com>
---
| 1 +
gcc/testsuite/g++.dg/spellcheck-stdlib.C | 2 ++
gcc/testsuite/gcc.dg/spellcheck-stdlib-2.c | 8 ++++++++
3 files changed, 11 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/spellcheck-stdlib-2.c
--git a/gcc/c-family/known-headers.cc b/gcc/c-family/known-headers.cc
index 3484c867ca0..14855bd75c7 100644
--- a/gcc/c-family/known-headers.cc
+++ b/gcc/c-family/known-headers.cc
@@ -182,6 +182,7 @@ get_stdlib_header_for_name (const char *name, enum stdlib lib)
{"strchr", {"<string.h>", "<cstring>"} },
{"strcmp", {"<string.h>", "<cstring>"} },
{"strcpy", {"<string.h>", "<cstring>"} },
+ {"strerror", {"<string.h>", "<cstring>"} },
{"strlen", {"<string.h>", "<cstring>"} },
{"strncat", {"<string.h>", "<cstring>"} },
{"strncmp", {"<string.h>", "<cstring>"} },
diff --git a/gcc/testsuite/g++.dg/spellcheck-stdlib.C b/gcc/testsuite/g++.dg/spellcheck-stdlib.C
index fd0f3a9b8c9..33718b8034e 100644
--- a/gcc/testsuite/g++.dg/spellcheck-stdlib.C
+++ b/gcc/testsuite/g++.dg/spellcheck-stdlib.C
@@ -104,6 +104,8 @@ void test_cstring (char *dest, char *src)
// { dg-message "'#include <cstring>'" "" { target *-*-* } .-1 }
strcpy(dest, "test"); // { dg-error "was not declared" }
// { dg-message "'#include <cstring>'" "" { target *-*-* } .-1 }
+ strerror(0); // { dg-error "was not declared" }
+ // { dg-message "'#include <cstring>'" "" { target *-*-* } .-1 }
strlen("test"); // { dg-error "was not declared" }
// { dg-message "'#include <cstring>'" "" { target *-*-* } .-1 }
strncat(dest, "test", 3); // { dg-error "was not declared" }
diff --git a/gcc/testsuite/gcc.dg/spellcheck-stdlib-2.c b/gcc/testsuite/gcc.dg/spellcheck-stdlib-2.c
new file mode 100644
index 00000000000..61c17f350cb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/spellcheck-stdlib-2.c
@@ -0,0 +1,8 @@
+/* { dg-options "-Wimplicit-function-declaration" } */
+
+/* Missing <string.h>. */
+void test_string_h (void)
+{
+ strerror (0); /* { dg-warning "implicit declaration of function 'strerror'" } */
+ /* { dg-message "'strerror' is defined in header '<string.h>'" "" { target *-*-* } .-1 } */
+}
--
2.41.0
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