Even if you keep your code in a separate file, if you link to GPL code, according to the FSF, your code should be GPL. The law says otherwise but they would still sue you.
@stevedice so, what about dual-licensed code like wine/crossover or qt?
Linking to GPL code means code must be COMPATIBLE with GPL and resulting work must be distrubuted with same GPL. But same code, that not becomes part of this work can use different license if code author deside use it. You can dual-license your file with MIT/GPL and use it in GPL software. It will use GPL when build in GPL projects, and MIT in non-GPL. You cannot use BSD code in GPL software because BSD adds requirements that not compatible with GPL (but explicit dual-licensing GPL/BSD seems to be possible)
Even if you keep your code in a separate file, if you link to GPL code, according to the FSF, your code should be GPL. The law says otherwise but they would still sue you.
@stevedice so, what about dual-licensed code like wine/crossover or qt?
Linking to GPL code means code must be COMPATIBLE with GPL and resulting work must be distrubuted with same GPL. But same code, that not becomes part of this work can use different license if code author deside use it. You can dual-license your file with MIT/GPL and use it in GPL software. It will use GPL when build in GPL projects, and MIT in non-GPL. You cannot use BSD code in GPL software because BSD adds requirements that not compatible with GPL (but explicit dual-licensing GPL/BSD seems to be possible)