layout explanation 1, ctpcapi.h this is the basic c api. c program will need to include this file and link to three shared libraries: thostmduserapi.so & thosttraderapi.so & libctpcapi.so. 2, the directory cpp2c will be compiled into libctpcapi.so. And building into libctpcapi.so is the only usage of this directory. 3, cpp_api is the origin c++ api. when compiling cpp2c, this directory will be used. 4, the directory bin is temp folder. no need to worry. 5, Makefile is Makefile. you can take a look. 6, others is others. no need to worry. 7, the directory server: I use c api to build the md server and trader server. 8, tags is tags. no need to worry.