Error: Library "strings" declared twice

[luren5]

while I imported the library and compiled, it return warning

strings.sol:37:1: Warning: Source file does not specify required compiler version!Consider adding "pragma solidity ^0.4.7
library strings {

then, added the "pragma solidity ^0.4.7" and compiled again, it returns error

[root@localhost contracts]# truffle compile
Compiling ./contracts/Ballot.sol...
Compiling ./contracts/strings.sol...
Compiling strings.sol...
Error compiling:

/home/xuhuan/contract/c2/contracts/strings.sol:39:1: Error: Library "strings" declared twice (will create ambiguities during linking).
library strings {
^
Spanning multiple lines.
The other declaration is here: strings.sol:39:1: 
library strings {
^
Spanning multiple lines.

[Arachnid]

It sounds like you're including the library more than once, via a relative path and an absolute path. What do your import statements look like?

[llixli]

I solved this problem using the full path to imported file

[sk4092]

use import './strings.sol'; while importing the library and keep both files in same directory