utils.h

#ifndef MIM_UTILS_H
#define MIM_UTILS_H

#include <stdbool.h>
#include <stdio.h>

/*
 * Set or unset the 'close_on_exec' flag on a given descriptor.
 *
 * As the name suggests, this causes the descriptor to be automatically closed at any exec*().
 * By default this flag is false, but it's a good idea to basically always set it.
 * Note that the flag is false for duplicated descriptors after dup2().
 */
void set_close_on_exec(int file_descriptor, bool value);

/*
 * Split a string into space-delimited parts.
 *
 * The result is an array of null-terminated strings, ending with NULL.
 * It must be freed with free_split_string().
 *
 * The resulting parts don't contain any spaces.
 * The result has always as many parts as they are spaces, plus 1.
 * In particular, for an empty string, the result is {"", NULL}.
 * An initial or final space, or two consecutive spaces, result in an empty-string part.
 */
char** split_string(const char* s);

void free_split_string(char** parts);

/*
 * Read a line from `file`.
 *
 * Read characters into buffer until a newline or EOF is encountered.
 * If we read anything (possibly just a newline), set buffer to a non-empty null-terminated string and return true.
 * Otherwise (immediate EOF), set buffer to empty string and return false.
 *
 * The newline is included, if we end at one.
 * If more than `size_of_buffer - 1` characters would be read, exit(1).
 * If a null character is read, exit(1).
 * On any error, exit(1).
 *
 * size_of_buffer must be at least 2.
 */
bool read_line(char* buffer, size_t size_of_buffer, FILE* file);

#endif