issue in file handling in c [closed] - c

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Hi i am trying to read two characters from a file and want to send it to uint8_t* as hexadecimal .
Code:
#include <stdio.h>
#include <stdint.h>
#include <inttypes.h>
int file_handling();
int main()
{
uint8_t *output ;
output=file_handling() ;
printf("\noutput_main --> %02x",output);
}
int file_handling()
{
uint8_t *output_hand ;
char c;
FILE *f_gets = fopen("filename", "r");
if(f_gets==NULL)
{
printf("Please point to a valid key file!\n");
fclose(f_gets);
return 0;
}
char str[3];
if( fgets (str, 3, f_gets)!=NULL )
{
/* writing content to stdout */
puts(str);
output_hand = (uint8_t *)(str);
puts(output_hand);
printf("\noutput %s --- %02x --> size --> %lu",str,*output_hand,sizeof(*output_hand));
}
fclose(f_gets);
return *output_hand;
}
following is output
we we
output we --- 77 --> size --> 1 output_main --> 65
what i can understand is 77 is ascii for w and 65 is ascii for e
but i want to put "we" which i suppose is a hex in uint8_t *output
where is the problem
in main ,if i use pointer "*output=file_handling()" instead of just output i get segmentation fault.
How to read value from a file and put it into uint8_t , where file is having hex characters,how fget identifies it as hex or char.
Thanks
file is a text file
ab
fe
ea
ce
1d
Basically
uint8_t *output;
*output = 0xFA ;
it works
but i want to read from above file and put it into output variable

Answer 1

You have plenty of problems, here's three of them:
You define str to be an array of two characters, which means it can only contain a single-character string. You then call fgets telling it that str it three characters, which means it can and will write out of bounds of your array.
You have declared file_handling to return an int value. You return the first character in the array string, and assign that to the pointer variable output in the main function. You then treat this pointer as a single int value.
In the main function you pass the pointer output but print it as an int value. There's a mismatch between the format specifier and the argument.
The first and third issues lead to undefined behavior.