int MLGetSymbol(MLINK link, char **s) gets a character string corresponding to the name of a symbol from the MathLink connection specified by link, storing the resulting string in s.
MLGetSymbol() allocates memory for the character string. You must call MLDisownSymbol() to disown this memory.
MLGetSymbol() creates a string that is terminated by \0.
See Section 2.13.4 and Section 2.13.12.