FCLOSEALL(3) Linux Programmer's Manual FCLOSEALL(3)

fcloseall - close all open streams

#define _GNU_SOURCE         /* See feature_test_macros(7) */
#include <stdio.h>
int fcloseall(void);

The fcloseall() function closes all of the calling process's open streams. Buffered output for each stream is written before it is closed (as for fflush(3)); buffered input is discarded.

The standard streams, stdin, stdout, and stderr are also closed.

This function returns 0 if all files were successfully closed; on error, EOF is returned.

For an explanation of the terms used in this section, see attributes(7).
Interface Attribute Value
fcloseall () Thread safety MT-Unsafe race:streams

The fcloseall() function does not lock the streams, so it is not thread-safe.

This function is a GNU extension.

close(2), fclose(3), fflush(3), fopen(3), setbuf(3)

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2021-03-22 GNU