https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90005
Bug ID: 90005
Summary: No error produced for the wrong type of string used in
gcc >= 5.0
Product: gcc
Version: 8.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: pawel.wrobel at nielsen dot com
Target Milestone: ---
Hello,
I have the question regarding the following behaviour of gcc 8.3 (it behaves
the same way from version 5.0 up to 8.3 - when I tested with the
https://gcc.godbolt.org/).
When I compile following program (it has an obvious omission - missing .c_str()
conversion of std::string to char*)
#include <stdio.h>
#include <string>
int main()
{
std::string txt("there");
printf("Hello %s ! \n", txt);
}
On the gcc 4.9 and before - it correctly notifies me with an error like :
<source>: In function 'int main()':
<source>:6:30: error: cannot pass objects of non-trivially-copyable type
'std::string {aka class std::basic_string<char>}' through '...'
printf("Hello %s ! \n", txt);
Compiler returned: 1
However, starting from the gcc 5.0 and above (gcc 8.3 included) - no error is
generated - and the binary is being produced. It obviously prints the garbage
when run ("Hello (`e !"). So lack of the error should be considered as an bug ?
Or maybe do I need to provide some special flag for this error message to
appear and stop the compilation in gcc 5.0 and above ?
Both the gcc <= 4.9 works correctly here (and the newer clang compilers also
point out this error correctly). Can I make the gcc >= 5.0 to generate an error
here with some flag ?
