我正在尝试在linux中学习c程序。我正在使用fopen（）函数打开文本文件。我的程序正在抛出Segmentation fault（核心转储）。这是代码：
/* This program is written to demonstrate the uses for
getopt_long function to define option argument in linusx system*/
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* The name of this program. */
const char* program_name;
FILE *file, *file1;
char sentence[1035];
/* Prints Usage information for this program to STREAM(Typically
stdout or stderr), and exit the program with EXIT_CODE. Does not
return. */
void print_usage(FILE* stream, int exit_code)
{
fprintf (stream," Usage: %s options [ inputfile...]\n", program_name);
fprintf (stream,
" -h --help Display this usage information.\n"
" -o --output filename write output to file \n"
" -v --verbose Print verbose messages.\n");
exit (exit_code);
}
/* Main program entry point . ARDC contains number of argument list
elements, ARGV is an array of pointers to them.*/
int main (int argc , char* argv[])
{
int next_option;
const char filename[1000];
/* A string listing valid short option letters. */
const char* const short_options = "ho:v";
/*An array describing valid long options. */
const struct option *long_options = {
{ "help", 0, NULL, 'h'},
{ "output", 1, NULL, 'o'},
{ "verbose", 0, NULL, 'v'},
{ NULL, 0, NULL, 0} //Required at end of array
};
/* The name of the file to reciev program out, or NULL for
standard output.*/
const char* output_filename = NULL;
/* Where to dispaly verbose messagae.*/
int verbose = 0;
/*Remember the name of the program, to incorporate in messages.
The name is stored in argv[0]. */
program_name = argv[0];
do {
next_option = getopt_long (argc, argv, short_options,
long_options, NULL);
switch (next_option)
{
case 'h': /* -h or --help */
/* User has requested usage information. Print it to standard
output, and exit with exit code zero (normal terminatio ). */
print_usage (stdout, 0);
case 'o': /* -o or --output */
/* This option takes an argument, the name of the output file . */
output_filename = optarg;
file = popen("/bin/ls /etc/", "r");
if (file == NULL){
printf("Failed to run command\n");
exit(1);
}
strcpy(filename, "/home/biki/Desktop/C_Prog/program2/");
strcat(filename,output_filename);
file1 = fopen(filename, 'w+');
if (file1 == NULL)
{
printf("Error while opening text.txt");
exit(1);
}
while(fgets(sentence, sizeof(sentence)-1, file) != NULL)
{
fprintf(file1, "%s", sentence);
}
/*close file*/
pclose(file1);
pclose(file);
case 'v': /* -v or --verbose */
/* Print usage information to standard error, and exit with exit
code one (indication abnormal termination). */
print_usage (stderr, 1);
case -1: /* done with options. */
break;
default : /*Something else. unexpected. */
abort ();
}
}
while (next_option != -1);
if (verbose) {
int i;
for (i = optind; i < argc; ++i)
printf ("Argument: %s\n", argv[i]);
}
/* the main program goes here */
return 0;
}
这是gdb
Program received signal SIGSEGV, Segmentation fault.
_IO_new_file_fopen (fp=fp@entry=0x555555757120,
filename=filename@entry=0x7fffffffdb60 "/home/biki/Desktop/C_Prog/program2/text.txt",
mode=mode@entry=0x772b <error: Cannot access memory at address 0x772b>,
is32not64=is32not64@entry=1) at fileops.c:270
270 fileops.c: No such file or directory.
(gdb) backtrace
#0 _IO_new_file_fopen (fp=fp@entry=0x555555757120,
filename=filename@entry=0x7fffffffdb60 "/home/biki/Desktop/C_Prog/program2/text.txt",
mode=mode@entry=0x772b <error: Cannot access memory at address 0x772b>,
is32not64=is32not64@entry=1) at fileops.c:270
#1 0x00007ffff7a7ff84 in __fopen_internal (
filename=0x7fffffffdb60 "/home/biki/Desktop/C_Prog/program2/text.txt",
mode=0x772b <error: Cannot access memory at address 0x772b>, is32=1)
at iofopen.c:86
#2 0x0000555555554ced in main (argc=3, argv=0x7fffffffe038)
at getopt_long.c:82
谁能告诉我这是什么问题？