perror example in C

Header file:

    stdio.h

Synopsis:

    void perror(const char *str);

Description:

     Prints error string str and system error message corresponds to errno.

perror function C example:

  #include<stdio.h>
  #include<string.h>
  #include<errno.h>
  int main(int argc, char **argv) {
        FILE *fp;
        char *errmsg;
        fp = fopen(argv[1], "r");

        if (fp == NULL) {
                /* errno - available in errno.h */
                errmsg = strerror(errno);
                perror(errmsg);
                return;
        }
        fclose(fp);
        return 0;
  }

  Output:

  No such file or directory: No such file or directory