Part of my program is to calculate sqrt of float number.
When I write sqrt(1.0f); I success to compile the program,but when I write sqrt(-1.0f);
the compilation fails with undefined reference to 'sqrt' - I suppose that in this case the nan value will be returned...
I compile the program uing gcc.
When I compile it with visual studio it is compiled successfuly with negative argument to sqrt.
How the problem could be solved
Thank you
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Pascal Cuoq
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Yakov
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gcc myprog.c -o myprog -lm the -l to include a library m for the math library -lm. – old_timer Jan 08 '12 at 19:41
2 Answers
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You have to add the -lm flag on most Unix-based systems, as in:
Compile using:
gcc -c file.c
and then link using:
gcc -o program file.o -lm
Or if you don't want to separate the two compilation steps, simply write:
gcc -o program file.c -lm
4
Link with -lm to link with the math library
Manuel Selva
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Can you please give a reason for it. I tried including
in headers, but then facing the error as mentioned in the question. – Akash Chandwani Nov 27 '16 at 18:06