C process control

C process control refers to a group of functions in the standard library of the C programming language implementing basic process control operations.^[1][2] The process control operations include actions such as termination of the program with various levels of cleanup, running an external command interpreter or accessing the list of the environment operations.

The process control functions are defined in the stdlib.h header (cstdlib header in C++).

The following is an example of communicating with the system environment in C.

#include <stdio.h>
#include <stdlib.h>

int main() {
    char* path = getenv("PATH");
    if (!path) {
        fprintf(stderr, "PATH environment variable not found.\n");
    } else {
        printf("PATH variable: %s\n", path);
    }

    printf("Listing current directory contents using system(\"ls\"):\n");
    int ret = system("ls");

    if (ret == -1) {
        fprintf(stderr, "system() call failed!");
    }

    return 0;
}

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