https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101999
Bug ID: 101999
Summary: strdup on `gcc -std=c99` gives segfault
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: piertoni at protonmail dot com
Target Milestone: ---
Created attachment 51330
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51330&action=edit
source
strdup is not a part of -std=c99 but the following reproducer program compiles
and gives segfault.
```
#include <stdio.h>
#include <string.h>
int main() {
const char *words[] = {"hi", "I", "Am", "testing"};
for (int i=0; i < 4; i++)
{
char * copy = strdup(words[i]);
printf("%s", copy);
}
}
```
Compiled on x86_64 GNU/Linux with:
`gcc -std=c99 bug.c && ./a.out`
gives warnings:
`
bug.c: In function ‘main’:
bug.c:9:23: warning: implicit declaration of function ‘strdup’; did you mean
‘strcmp’? [-Wimplicit-function-declaration]
char * copy = strdup(words[i]);
^~~~~~
strcmp
bug.c:9:23: warning: initialization of ‘char *’ from ‘int’ makes pointer from
integer without a cast [-Wint-conversion]
`
and Segfault as a result.
The same compiles correctly if -std=c99 is not used or if strdup is specified
as
`extern char *strdup(const char *s)`
Also clang with same options compiles correctly (giving appropriate warnings).
Result of `gcc -v`:
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/8/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 8.3.0-6'
--with-bugurl=file:///usr/share/doc/gcc-8/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr
--with-gcc-major-version-only --program-suffix=-8
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie
--with-system-zlib --with-target-system-zlib --enable-objc-gc=auto
--enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--enable-offload-targets=nvptx-none --without-cuda-driver
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 8.3.0 (Debian 8.3.0-6)
