gcc main函数

GCC:gcc/main.c   #include "config.h"#include "system.h"#include "coretypes.h"#include "tm.h"#include "diagnostic-core.h"#include "toplev.h"int main (int argc, char **argv);/* We define main() to call toplev::main(), which is defined in toplev.c.   We do this in a separate file in order to allow the language front-end   to define a different main(), if it so desires.  */intmain (int argc, char **argv){  toplev toplev (NULL, /* external_timer */   true /* init_signals */);  return toplev.main (argc, argv);}