std::fclose

 

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Defined in header <cstdio>
int fclose(std::FILE* stream );

Closes the given file stream and writes any unwritten data from stream's buffer to the associated output device. Any unread buffered data are discarded.

Whether or not the operation succeeds, the stream is no longer associated with a file, and the buffer allocated by std::setbuf or std::setvbuf, if any, is also disassociated and deallocated if automatic allocation was used.

If any data are written to an output device, returning from std::fclose establishes an observable checkpoint.

(since C++26)

The behavior is undefined if the value of the pointer stream is used after std::fclose returns.

Parameters

stream

-

the file stream to close

Return value

​0​ on success, EOF otherwise.

Example

Run this code

#include <cstdio>#include <cstdlib>   int main(){int is_ok =EXIT_FAILURE; FILE* fp =std::fopen("/tmp/test.txt", "w+");if(!fp){std::perror("File opening failed");return is_ok;}   int c;// Note: int, not char, required to handle EOFwhile((c =std::fgetc(fp))!=EOF)// Standard C I/O file reading loopstd::putchar(c);   if(std::ferror(fp))std::puts("I/O error when reading");elseif(std::feof(fp)){std::puts("End of file reached successfully"); is_ok =EXIT_SUCCESS;}   std::fclose(fp);return is_ok;}

Output:

End of file reached successfully

See also

fopen	opens a file (function)
freopen	open an existing stream with a different name (function)
close	flushes the put area buffer and closes the associated file (public member function of std::basic_filebuf<CharT,Traits>)
C documentation for fclose