我编译的时候用了这条命令 gcc -o test test.c -I/usr/include/SDL
程序也进行初始化了,可是编译以后老是出现这样的信息
/tmp/ccGnlS6J.o(.text+0xe3): In function `putpixel':
: undefined reference to `SDL_LockSurface'
/tmp/ccGnlS6J.o(.text+0x136): In function `putpixel':
: undefined reference to `SDL_UpdateRect'
/tmp/ccGnlS6J.o(.text+0x15d): In function `putpixel':
: undefined reference to `SDL_UnlockSurface'
怎么回事呢