Advanced Programming in the UNIX Environment: Second Edition [Electronic resources] نسخه متنی

7.2. main Function

A C program starts execution with a function called main. The prototype for the main function is

int main(int

argc , char *

argv []);

where

argc is the number of command-line arguments, and

argv is an array of pointers to the arguments. We describe these arguments in Section 7.4.

When a C program is executed by the kernelby one of the exec functions, which we describe in Section 8.10a special start-up routine is called before the main function is called. The executable program file specifies this routine as the starting address for the program; this is set up by the link editor when it is invoked by the C compiler. This start-up routine takes values from the kernelthe command-line arguments and the environmentand sets things up so that the main function is called as shown earlier.