“undefined reference to `strnstr'” when installing cminpack

Question

I am installing cminpack 1.1.2 on a clean install of Ubuntu 10.10.

When running sudo make in the cminpack folder, the folloing error occurs at 52%:

[ 52%] Building C object examples/CMakeFiles/genf77tests.dir/genf77tests.c.o
/usr/lib/cminpack-1.1.2/examples/genf77tests.c: In function ‘main’:
/usr/lib/cminpack-1.1.2/examples/genf77tests.c:44: warning: assignment makes pointer from integer without a cast
/usr/lib/cminpack-1.1.2/examples/genf77tests.c:86: warning: comparison between pointer and integer
Linking C executable genf77tests
CMakeFiles/genf77tests.dir/genf77tests.c.o: In function `main':
genf77tests.c:(.text+0xb5): undefined reference to `strnstr'
genf77tests.c:(.text+0x2a9): undefined reference to `strnstr'
collect2: ld returned 1 exit status
make[2]: *** [examples/genf77tests] Error 1
make[1]: *** [examples/CMakeFiles/genf77tests.dir/all] Error 2
make: *** [all] Error 2

I have looked inside genf77tests.c, and #include <string.h> is present, so I don't see why there is a problem finding strnstr.

Is there anything I can do to fix this issue?

Answer 1

strnstr is not standard C; as far as I can see, it's provided on the BSD UNIX family.

Still, if the only problem in your compilation is that one you can provide its prototype¹ and add to the files to be compiled one that contains its implementation (for example this one).

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1. Actually, you may not even need it: if the compilation gets to the linking stage and fails just there, you can solve throwing in just the implementation of strnstr.

Answer 2

strnstr is a non-standard function. Specifically, it is not included in Glibc. Whoever wrote genf77test.c did not test it on Linux/glibc...