"#include" a text file in a C program as a char[]

I'd suggest using (unix util)xxd for this.you can use it like so

$ echo hello world > a$ xxd -i a

outputs:

unsigned char a[] = {  0x68, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x77, 0x6f, 0x72, 0x6c, 0x64, 0x0a};unsigned int a_len = 12;

The question was about C but in case someone tries to do it with C++11 then it can be done with only little changes to the included text file thanks to the new raw string literals:

In C++ do this:

const char *s =#include "test.txt";

In the text file do this:

R"(Line 1Line 2Line 3Line 4Line 5Line 6)"

So there must only be a prefix at the top of the file and a suffix at the end of it. Between it you can do what you want, no special escaping is necessary as long as you don't need the character sequence )". But even this can work if you specify your own custom delimiter:

R"=====(Line 1Line 2Line 3Now you can use "( and )" in the text file, too.Line 5Line 6)====="

You have two possibilities:

1. Make use of compiler/linker extensions to convert a file into a binary file, with proper symbols pointing to the begin and end of the binary data. See this answer: Include binary file with GNU ld linker script.
2. Convert your file into a sequence of character constants that can initialize an array. Note you can't just do "" and span multiple lines. You would need a line continuation character (\), escape " characters and others to make that work. Easier to just write a little program to convert the bytes into a sequence like '\xFF', '\xAB', ...., '\0' (or use the unix tool xxd described by another answer, if you have it available!):

Code:

#include <stdio.h>int main() {    int c;    while((c = fgetc(stdin)) != EOF) {        printf("'\\x%X',", (unsigned)c);    }    printf("'\\0'"); // put terminating zero}

(not tested). Then do:

char my_file[] = {#include "data.h"};

Where data.h is generated by

cat file.bin | ./bin2c > data.h