generating random number with Maxwell distribution in C

I need 10000 random number that distributed with Maxwell distribution. For normal distribution I know that I have to use Box-Muller transform but my question is that why

 gamma_distribution

is defined as a variable( or anything that I don't know) by default? Is "gamma_distribution" a function that gives numbers with normal distribution? If yes, is this possible for Maxwell distribution? If not, what should I do? Thanks for any tips.