Usage

#include <sodium.h>

int main(void)
{
    if (sodium_init() == -1) {
        return 1;
    }
    ...
}

sodium.h is the only header that has to be included.

The library is called sodium (use -lsodium to link it), and proper compilation/linker flags can be obtained using pkg-config on systems where it is available:

CFLAGS=$(pkg-config --cflags libsodium)
LDFLAGS=$(pkg-config --libs libsodium)

sodium_init() initializes the library and should be called before any other function provided by Sodium. The function can be called more than once, but it should not be executed by multiple threads simultaneously. Add appropriate locks around the function call if this scenario can happen in your application.

After this function returns, all of the other functions provided by Sodium will be thread-safe.

sodium_init() doesn't perform any memory allocations. However, on Unix systems, it opens /dev/urandom and keeps the descriptor open so that the device remains accessible after a chroot() call. Multiple calls to sodium_init() do not cause additional descriptors to be opened.