File I/O

abs_fs is a thin set of helpers around fopen, remove, and rename: check a file exists, read or write a whole file, delete it, or move it. All functions take platform-native paths.

#include "abscom/abs.h"

API

Function	Description
int abs_fs_exists(const char *path)	1 if the file can be opened for reading, 0 otherwise.
int abs_fs_read_file(const char *path, char **out_data, size_t *out_size)	Read a whole file into a NUL-terminated buffer (caller frees).
int abs_fs_write_file(const char *path, const void *data, size_t size)	Write size bytes to a file (creates or truncates).
int abs_fs_remove(const char *path)	Delete a file; 0 on success, -1 on failure.
int abs_fs_rename(const char *from, const char *to)	Rename/move a file; 0 on success, -1 on failure.

Functions return 0 on success and -1 on error. For abs_fs_read_file, *out_data is always NUL-terminated (buf[n] == '\0'), and the caller is responsible for free(*out_data).

Example

#include "abscom/abs.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(void) {
    const char *data = "hello abscom file\nsecond line";

    if (abs_fs_write_file("notes.txt", data, strlen(data)) != 0) return 1;
    if (!abs_fs_exists("notes.txt")) return 1;

    char *buf = NULL;
    size_t n = 0;
    if (abs_fs_read_file("notes.txt", &buf, &n) == 0) {
        printf("read %zu bytes\n%s", n, buf);
        free(buf);
    }

    abs_fs_rename("notes.txt", "notes-copy.txt");
    abs_fs_remove("notes-copy.txt");
    return 0;
}

For the Python-style fopen_safe / read_file / write_file / close_file helpers that return var objects, see runtime-files.md.

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