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#include <stdio.h>
#include "stdlib.h"
#include "nonstd/io.h"
/** open a file stream **/
FILE * fopen(const char * restrict filename, const char * restrict mode)
{
struct __FILE *base = __libc(FILE_STREAMS);
struct __FILE *f = base;
/* find the next available stream */
while (f->next != NULL) {
f = f->next;
}
/* use a stream from the guaranteed space if possible */
/* otherwise, allocate a new stream */
if (f < base + FOPEN_MAX) {
f->next = f + 1;
} else {
f->next = malloc(sizeof(*f->next));
}
/* if we had to allocate, but that failed, we're out of memory */
if (f->next == NULL) {
return NULL;
}
/* open the new stream */
f->next->prev = f;
f = f->next;
f->fd = -1;
if (freopen(filename, mode, f) == NULL) {
if (f < base + FOPEN_MAX) {
} else {
free(f);
}
return NULL;
}
/*
RETURN_SUCCESS(a pointer to the new file stream);
RETURN_FAILURE(CONSTANT(NULL));
*/
return f;
}
/***
opens a file stream associated with the file ARGUMENT(filename).
The type of file and allowed operations are determined by ARGUMENT(mode):
FLAG(LITERAL(r), text file; read-only)
FLAG(LITERAL(w), text file; write-only; truncate to 0 bytes)
FLAG(LITERAL(a), text file; append)
FLAG(LITERAL(rb), binary file; read-only)
FLAG(LITERAL(wb), binary file; write-only; truncate to 0 bytes)
FLAG(LITERAL(ab), binary file; append)
FLAG(LITERAL(r+), text file; update (read and write))
FLAG(LITERAL(w+), text file; update (read and write); truncate to 0 bytes)
FLAG(LITERAL(a+), text file; update (read and write); append data to end of file)
FLAG(LITERAL(r+b), binary file; update (read and write))
FLAG(LITERAL(rb+), binary file; update (read and write))
FLAG(LITERAL(w+b), binary file; update (read and write); truncate to 0 bytes)
FLAG(LITERAL(wb+), binary file; update (read and write); truncate to 0 bytes)
FLAG(LITERAL(a+b), binary file; update (read and write); append data to end of file)
FLAG(LITERAL(ab+), binary file; update (read and write); append data to end of file)
File streams are opened in fully buffered mode if and only if
ARGUMENT(filename) is not an interactive device.
The error and end-of-file indicators are cleared.
***/
/*
STDC(1)
*/
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