问题
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
回答1:
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
回答2:
Link with -lm to link with the math library
来源：https://stackoverflow.com/questions/8780603/undefined-reference-to-sqrt