perror.c

里面包含很多c语言的源码

/* Demonstration of error handling with perror() and errno. */

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

int main( void )
{
    FILE *fp;
    char filename[80];

    printf("Enter filename: ");
    gets(filename);

    if (( fp = fopen(filename, "r")) == NULL)
    {
        perror("You goofed!");
        printf("errno = %d.\n", errno);
        exit(1);
    }
    else
    {
        puts("File opened for reading.");
        fclose(fp);
    }
    return 0;
}